Message transmission method and device

Abstract

A message transmission method and device relating to the field of communications technologies are described that improve an anti-interference capability in message transmission. The method includes generating a scrambling code according to a scrambling code initialization seed, wherein the scrambling code initialization seed meets the following expression: c.sub.init=R.Math.2.sup.a.sup.7+P.Math.(.sup.n.sup.f mod .sup.k+1).Math.2.sup.b.sup.7 and then scrambling a message according to the scrambling code. The method further includes sending the scrambled message to a terminal on a physical downlink shared channel. Because the first time parameter has different values at at least two different moments, scrambling codes determined at the at least two corresponding different moments are different. Therefore, a possibility at which the base station uses a same scrambling code to scramble a same system message repeatedly in a time period is reduced, so that an anti-interference capability in system message transmission is improved.

Claims

1. A message sending method, comprising: generating a scrambling code according to a scrambling code initialization seed, wherein the scrambling code initialization seed meets the following expression:
c.sub.init=R.Math.2.sup.a.sup.7+P.Math.(.sup.n.sup.f mod .sup.k+1).Math.2.sup.b.sup.7 where c.sub.init is the scrambling code initialization seed, R is a function of n.sub.RNTI, a.sub.7 is a non-negative integer, P is a function of a cell identity, n.sub.f is the a frame number of a message, k is a prime number, and b.sub.7 is a non-negative integer; scrambling the message according to the scrambling code to render a scrambled message; and sending the scrambled message to a terminal on a physical downlink shared channel, wherein the message is a system message, a part of a system message, an encoded system message, or a part of an encoded system message, and wherein the system message is a system information block.

2. The method according to claim 1, wherein R is equal to the n.sub.RNTI, P is equal to N.sub.ID.sup.cell+1, where N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

3. The method according to claim 1, wherein a.sub.7 is equal to a number of bits occupied by (.sup.n.sup.f mod .sup.k+1).Math.P, where P is equal to N.sub.ID.sup.cell+1, N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

4. The method according to claim 1, wherein the frame number n.sub.f is a number of a radio frame in which a start position for sending the message is located.

5. The method according to claim 1, wherein b.sub.7 is equal to 0.

6. A message receiving method, the method comprising: generating a scrambling code according to a scrambling code initialization seed, wherein the scrambling code initialization seed meets the following expression:
c.sub.init=R.Math.2.sup.a.sup.7+P.Math.(.sup.n.sup.f mod .sup.k+1).Math.2.sup.b.sup.7 where c.sub.init is the scrambling code initialization seed, R is a function of n.sub.RNTI, a.sub.7 is a non-negative integer, P is a function of a cell identity, n.sub.f is the a frame number of a message, k is a prime number, and b.sub.7 is a non-negative integer; receiving a scrambled message on a physical downlink shared channel; and descrambling the scrambled message according to the scrambling code for acquiring the message, wherein the message is a system message, a part of a system message, an encoded system message, or a part of an encoded system message, and wherein the system message is a system information block.

7. The method according to claim 6, wherein R is equal to the n.sub.RNTI, P is equal to N.sub.ID.sup.cell+1, where N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

8. The method according to claim 6, wherein a.sub.7 is equal to a number of bits occupied by (.sup.n.sup.f mod .sup.k+1).Math.P, where P is equal to N.sub.ID.sup.cell+1, N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

9. The method according to claim 6, wherein the frame number n.sup.f is a number of a radio frame in which a start position for sending the message is located.

10. The method according to claim 6, wherein b.sub.7 is equal to 0.

11. A network side device, comprising: at least one processor, and a non-transitory computer-readable medium storing computer-executable instructions that, when executed by the at least one processor, facilitate the network side device carrying out a method comprising: generating a scrambling code according to a scrambling code initialization seed, wherein the scrambling code initialization seed meets the following expression:
c.sub.init=R.Math.2.sup.a.sup.7+P.Math.(.sup.n.sup.f mod .sup.k+1).Math.2.sup.b.sup.7 where c.sub.init is the scrambling code initialization seed, R is a function of n.sub.RNTI, a.sub.7 is a non-negative integer, P is a function of a cell identity, n.sub.f is the a frame number of a message, k is a prime number, and b.sub.7 is a non-negative integer; scrambling the message according to the scrambling code to render a scrambled message; and sending the scrambled message to a terminal on a physical downlink shared channel, wherein the message is a system message, a part of a system message, an encoded system message, or a part of an encoded system message, and wherein the system message is a system information block.

12. The device according to claim 11, where R is equal to the n.sub.RNTI, P is equal to N.sub.ID.sup.cell+1, where N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

13. The device according to claim 11, wherein a.sub.7 is equal to a number of bits occupied by (.sup.n.sup.f mod .sup.k+1).Math.P, where P is equal to N.sub.ID.sup.cell+1, N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

14. The device according to claim 11, wherein the frame number n.sub.f is a number of a radio frame in which a start position for sending the message is located.

15. The device according to claim 11, wherein b.sub.7 is equal to 0.

16. A communication device, comprising: at least one processor, and a non-transitory computer-readable medium storing computer-executable instructions that, when executed by the at least one processor, facilitate the communication device carrying out a method comprising: generating a scrambling code according to a scrambling code initialization seed, wherein the scrambling code initialization seed meets the following expression:
c.sub.init=R.Math.2.sup.a.sup.7+P.Math.(.sup.n.sup.f mod .sup.k+1).Math.2.sup.b.sup.7 where c.sub.init is the scrambling code initialization seed, R is a function of n.sub.RNTI, a.sub.7 is a non-negative integer, P is a function of a cell identity, n.sub.f is the a frame number of a message, k is a prime number, and b.sub.7 is a non-negative integer; receiving a scrambled message on a physical downlink shared channel; and descrambling the scrambled message according to the scrambling code for acquiring the message, wherein the message is a system message, a part of a system message, an encoded system message, or a part of an encoded system message, and wherein the system message is a system information block.

17. The device according to claim 16, where R is equal to n.sub.RNTI, P is equal to N.sub.ID.sup.cell+1, where N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

18. The device according to claim 16, wherein a.sub.7 is equal to a number of bits occupied by (.sup.n.sup.f mod .sup.k+1).Math.P, where P is equal to N.sub.ID.sup.cell+1, N.sub.ID.sup.cell is the cell identity, and k is equal to 61.

19. The device according to claim 16, wherein the frame number n.sub.f is a number of a radio frame in which a start position for sending the message is located.

20. The device according to claim 16, wherein b.sub.7 is equal to 0.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic flowchart of a message transmission method according to an embodiment of this application;

(2) FIG. 2 is a schematic structural diagram of a radio frame in LTE;

(3) FIG. 3 is a schematic flowchart of a message transmission method according to an embodiment of this application;

(4) FIG. 4a is a schematic structural diagram of a base station according to an embodiment of this application;

(5) FIG. 4b is a schematic structural diagram of hardware of a base station according to an embodiment of this application;

(6) FIG. 5a is a schematic structural diagram of a terminal according to an embodiment of this application;

(7) FIG. 5b is a schematic structural diagram of hardware of a terminal according to an embodiment of this application;

(8) FIG. 6 is a schematic diagram of a communications system according to an embodiment of this application;

(9) FIG. 7a is a schematic structural diagram of a base station according to an embodiment of this application;

(10) FIG. 7b is a schematic structural diagram of hardware of a base station according to an embodiment of this application;

(11) FIG. 8a is a schematic structural diagram of a terminal according to an embodiment of this application;

(12) FIG. 8b is a schematic structural diagram of hardware of a terminal according to an embodiment of this application; and

(13) FIG. 9 is a schematic diagram of a communications system according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

(14) The following further describes the embodiments of this application in detail with reference to the accompanying drawings.

(15) The embodiments of this application may be applied to an LTE (Long Term Evolution) system, or may be applied to other wireless communications systems, such as a GSM (Global System for Mobile Communications), a UMTS (Universal Mobile Telecommunications System), a CDMA (Code Division Multiple Access) system, and a new network system such as a 5G (5th-Generation) network system.

(16) Abase station in the embodiments of this application may be configured to perform conversion between a received over-the-air frame and an IP (Internet Protocol) packet, and serve as a router between a wireless terminal and a remaining part of an access network. The remaining part of the access network may include an IP network. The base station in the embodiments of this application may be further configured to coordinate attribute management on an air interface. For example, the base station in the embodiments of this application may be a BTS (base transceiver station) in a GSM system or a CDMA system, may be a NodeB in WCDMA (Wideband Code Division Multiple Access), or may be an eNB (evolved NodeB) in an LTE system. This is not limited in the embodiments of this application.

(17) A terminal in the embodiments of this application may be a device configured to provide a user with voice and/or data connectivity, a handheld device with a wireless connection function, or another processing device connected to a wireless modem. Alternatively, the terminal may be a wireless terminal. The wireless terminal may communicate with one or more core networks through a RAN (radio access network). The wireless terminal may be a mobile terminal, such as a mobile phone (or referred to as a “cellular” phone) or a computer with a mobile terminal. For example, the computer with a mobile terminal may be a portable, pocket-sized, handheld, computer built-in, or in-vehicle mobile apparatus, which exchanges voice and/or data with the radio access network. For example, alternatively, the wireless terminal may be a device such as a PCS (personal communication service) phone, a cordless phone, a SIP (Session Initiation Protocol) phone, a WLL (wireless local loop) station, or a PDA (personal digital assistant). The wireless terminal may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a mobile, a remote station, an access point, a remote terminal, an access terminal, a user terminal, a user agent, a user device, user equipment, or the like.

(18) In the embodiments of this application, a time variable is added in a scrambling code generation process so that, among scrambling codes generated by the base station, scrambling codes generated at some two different moments are different. Because the scrambling codes determined at the two different moments are different, anti-interference performance in system message transmission is improved.

Embodiment 1

(19) For a system message such as a MIB transmitted on a physical broadcast channel, specifically, as shown in FIG. 1, a message sending method in this embodiment of this application includes the following steps.

(20) Step 100: A base station generates a scrambling code according to a first time parameter.

(21) It should be noted that the first time parameter has different values at at least two different moments in this embodiment of this application. Because the first time parameter has different values at the at least two different moments, scrambling codes generated at the at least two corresponding different moments are different. Therefore, a possibility at which the base station uses a same scrambling code to scramble a same system message repeatedly in a time period is reduced, so that an anti-interference capability in system message transmission is improved.

(22) Step 110: The base station scrambles a system message according to the scrambling code.

(23) It should be noted that, in this embodiment of this application, the system message may be a complete system message, or may be a part of a complete system message. The system message may be an encoded system message, or may be an uncoded system message. For example, when the complete system message is a MIB, the system message in this embodiment of this application may be the MIB, or may be a part of a MIB. When the system message in this embodiment of this application is a MIB, the MIB may be an encoded MIB, or may be a MIB before encoding. When the system message in this embodiment of this application is a part of a MIB, the part may be a part of an encoded MIB, or may be a part of an uncoded MIB.

(24) Step 120: The base station sends the scrambled system message to a terminal on a physical broadcast channel.

(25) For example, this embodiment of this application may also be applied to a channel other than the physical broadcast channel, for example, a channel such as a PDSCH (physical downlink shared channel), a PUSCH (physical uplink shared channel), a PDCCH (physical downlink control channel), a PUCCH (physical uplink control channel), a PCFICH (physical control format indicator channel), a PMCH (physical multicast channel), or a PRACH (physical random access channel). Names of the channels are all provided according to an LTE conventional naming rule, but the channels may have other names in another communications system. For example, the physical broadcast channel is named NPBCH (narrowband physical broadcast channel) in an NB-IoT (Narrowband Internet of Things). Further details are not described herein.

(26) Step 130: The terminal determines the first time parameter.

(27) For example, specifically, before sending the scrambled system message to the terminal, the base station sends a synchronization message to the terminal. The synchronization message may be used to indicate information about the first time parameter (or a part of information about the first time parameter; for example, when the first time parameter is a radio frame number in an NB-IoT system, the terminal may use the synchronization message to determine a value resulting from the radio frame number modulo 8). The first time parameter is a parameter used as a basis when the base station generates the scrambling code. The scrambling code is a scrambling code used by the base station to scramble the system message. The terminal determines the first time parameter according to the synchronization message sent by the base station. Step 130 in which the terminal determines the first time parameter may be performed before step 120, or may be performed after step 120. Alternatively, step 130 and step 120 may be simultaneously performed.

(28) Step 140: The terminal receives the scrambled system message on the physical broadcast channel.

(29) It should be understood that, when the base station sends the scrambled system message on another channel, the terminal receives the scrambled system message on the corresponding channel. A PDSCH is used as an example. When the base station sends the scrambled system message on the PDSCH, the terminal receives the scrambled system message on the PDSCH.

(30) Step 150: The terminal generates a scrambling code according to the first time parameter.

(31) For example, a manner in which the terminal generates the scrambling code according to the first time parameter is similar to a manner in which the base station generates the scrambling code according to the first time parameter. Details are not described herein again.

(32) It should be noted that there is no definite sequence for step 140 and step 130 and for step 140 and step 150; and step 130 is performed before step 150.

(33) Step 160: The terminal descrambles the received scrambled system message according to the scrambling code.

(34) For example, in this embodiment of this application, the first time parameter may be a function of at least one of a radio frame number, a timeslot number, a hyper frame number, or a symbol number.

(35) For example, the first time parameter is a function of the radio frame number. If the first time parameter is y, and the radio frame number is n.sub.f, y=f(n.sub.f), where f( ) is a function relationship between y and n.sub.f. A specific function relationship is determined according to a policy preset in the base station. For example, f( ) is a linear function, a slope is 2, and an intercept is 0. In this case, y=2.Math.n.sub.f. Alternatively, the first time parameter may be a function of any one or more of a radio frame number, a timeslot number, a hyper frame number, and a symbol number. Details are not described herein.

(36) For example, the radio frame number in this embodiment of this application may be a radio frame number in which a start position for sending the system message is located, or the radio frame number may be a radio frame number in which a last location for sending the system message is located, or the like. Cases of the timeslot number, the hyper frame number, and the symbol number are similar to this, and are not described herein.

(37) Because the radio frame number, the timeslot number, the hyper frame number, or the symbol number used to carry the system message varies with time, and the first time parameter is a function of at least one of the radio frame number, the timeslot number, the hyper frame number, or the symbol number, the first time parameter is also a physical quantity that varies with time, for example, a subframe number. Therefore, the scrambling code determined according to the first time parameter also varies with time.

(38) For example, alternatively, the first time parameter may be another physical quantity that varies with time, for example, a subframe number, without being limited to the radio frame number, the timeslot number, the hyper frame number, and the symbol number in this embodiment of this application.

(39) Specifically, as shown in FIG. 2, FIG. 2 is a schematic diagram of a frame structure of a radio frame in an LTE system. The radio frame may have another name in another communications system.

(40) A hyper frame includes one or more radio frames.

(41) For example, in this embodiment of this application, the first time parameter is any one of a radio frame number, a timeslot number, a hyper frame number, and a symbol number; or the first time parameter is a value resulting from any one of a radio frame number, a timeslot number, a hyper frame number, and a symbol number modulo a first modulus, where the first modulus is a positive integer.

(42) For example, a value of the first modulus may be 2.sup.n, where n is a positive integer. For example, the value of the first modulus may be 2, 4, 8, 16, 32, 64, 128, 256, or 512. Alternatively, the value of the first modulus may be a prime number, such as 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, or 61. For example, the first time parameter is the radio frame number. The first time parameter is a value resulting from the radio frame number modulo the first modulus. Therefore, a benefit of doing so is that complexity of system message detection by the terminal is reduced. Because the terminal may not know all information about the radio frame number when detecting the scrambled system message, the terminal needs to perform blind detection.

(43) For example, when the system message is a MIB, in an NB-IoT, the terminal may know, by using a synchronization message, a value resulting from the radio frame number modulo 8, and a minimum repetition period of the MIB is eight radio frames. Therefore, when the first modulus is 8, the terminal may be prevented from performing more blind detection operations on the radio frame number, and good anti-interference gains can be achieved. Therefore, in the NB-IoT, the first modulus is usually set to 8 when the system message is a MIB.

(44) In addition, in step 100, the base station generates the scrambling code according to the first time parameter. Specifically, the scrambling code may be directly generated according to the first time parameter. It is assumed that the first time parameter is the radio frame number, and the scrambling code may be the radio frame number represented by using a binary system.

(45) In addition, a base station may generate a scrambling code according to a first time parameter in two different implementations. One possible implementation is: The base station generates a scrambling code initialization seed according to the first time parameter, and then generates the scrambling code according to the scrambling code initialization seed. The other possible implementation is: The base station generates a scrambling code initialization seed according to the first time parameter and a first variable group, and then generates the scrambling code according to the scrambling code initialization seed. The first variable group includes at least one of a cell identity, a radio network temporary identifier RNTI, or a carrier identifier. It should be understood that, because a manner of generating the scrambling code according to the scrambling code initialization seed in this embodiment of this application is similar to that in the prior art, details are not described herein.

(46) The base station generates the scrambling code initialization seed according to the first time parameter. Specifically, the first time parameter is the radio frame number n.sub.f, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=n.sub.f. Alternatively, the first time parameter is a value resulting from the radio frame number n.sub.f modulo the first modulus k, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=n.sub.f mod k, where k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number. It should be noted that, c.sub.init=n.sub.f is used as an example, and linear deformation may also be performed on c.sub.init=n.sub.f. An example in which n.sub.f is represented by using a binary system is used. In this case, when a condition that a sequence length of the scrambling code initialization seed is not greater than a preset threshold is met, c.sub.init=n.sub.f may be deformed into c.sub.init=n.sub.f+N, where N is a preset constant binary sequence; or c.sub.init=n.sub.f may be deformed into c.sub.init=2.sup.n.Math.n.sub.f+N, where n is a quantity of bits occupied by the constant binary sequence N in c.sub.init. Alternatively, deformation similar to that performed on c.sub.init=n.sub.f may be performed when c.sub.init=n.sub.f mod k. It should be understood that, a manner used when the first time parameter is the timeslot number, the hyper frame number, or the symbol number is similar to that used when the first time parameter is the radio frame number n.sub.f, and details are not described herein.

(47) c.sub.init=2.sup.n.Math.n.sub.f+N is used as an example. It is assumed that a length of c.sub.init is 16, n.sub.f=1011 0111, N=1100 0101, and n=8. In this case, in c.sub.init, n.sub.f is higher eight bits, and N is lower eight bits. c.sub.init=1011 0111 1100 0101.

(48) The base station generates the scrambling code initialization seed according to the first time parameter and the first variable group. For example, the first time parameter is the radio frame number n.sub.f, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(n.sub.f.Math.2.sup.a.sup.1)+N.sub.ID.sup.cell, where a.sub.1 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(N.sub.ID.sup.cell.Math.2.sup.b.sup.1)+n.sub.f, where b.sub.1 is a quantity of bits occupied by n.sub.f in c.sub.init.

(49) In another possible example, the first time parameter is a value resulting from the radio frame number n.sub.f modulo the first modulus k, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.a.sup.2+N.sub.ID.sup.cell, where k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; and a.sub.2 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(N.sub.ID.sup.cell.Math.2.sup.b.sup.2+(n.sub.f mod k), where b.sub.2 is a quantity of bits occupied by (n.sub.f mod k) in c.sub.init.

(50) In another possible example, the first time parameter is a value resulting from the radio frame number n.sub.f (or the radio frame number plus an integer) modulo the first modulus k, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=[(n.sub.f+h)mod k)+w].sup.u.Math.P.Math.2.sup.a.sup.3+Q, or c.sub.init=[(n.sub.f+h)mod k)+w].sup.u.Math.P+Q.Math.2.sup.b.sup.3, where h is an integer, for example, is equal to 0 or 1; k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; w is an integer, for example, is equal to 0 or 1; u is a non-negative integer, for example, 0, 1, 2, or 3; P is a function of the cell identity and/or the radio frame number, for example, is equal to the cell identity N.sub.ID.sup.cell, or is equal to N.sub.ID.sup.cell.Math.(n.sub.f mod k).sup.v, where v is a positive integer; Q is a function of the cell identity, for example, is equal to the cell identity, or is equal to 0 (meaning that there is no parameter Q in the formula); a.sub.3 is a non-negative integer, for example, is equal to a quantity of bits occupied by Q in c.sub.init; and b.sub.3 is a non-negative integer, for example, is equal to a quantity of bits occupied by [(n.sub.f+h)mod k)+w].sup.u.Math.P in c.sub.init.

(51) In this embodiment, the scrambling may be bit-level scrambling. For example, modulo-2 addition may be performed on the scrambling code and to-be-scrambled information. The to-be-scrambled information may be a system message or a part of a system message, or may be an encoded system message or a part of an encoded system message.

(52) In this embodiment, the scrambling may be symbol-level scrambling. For example, the base station may first map the scrambling code from a bit form to a symbol form. A mapping method is not limited. For example, BPSK or QPSK modulation or another similar mapping method may be performed. Then, the base station performs a pointwise multiplication operation, a pointwise conjugate multiplication operation, or the like on the scrambling code in the symbol form and to-be-scrambled information. The to-be-scrambled information may be a system message obtained after code modulation or a part of a system message obtained after code modulation.

(53) It should be noted that, in this embodiment of this application, c.sub.init=N.sub.ID.sup.cell, n.sub.f, and n.sub.f mod k are all represented by using a binary system. c.sub.init=(n.sub.f.Math.2.sup.a.sup.1)+N.sub.ID.sup.cell is used as an example. When n.sub.f is multiplied by 2.sup.a.sup.1, N.sub.ID.sup.cell occupies lower a.sub.1 bits in c.sub.init.

(54) It should be noted that, in this embodiment of this application, the RNTI, the timeslot number, the symbol number, the hyper frame number, the cell identity, the carrier identifier, and the like may all participate in the generation of the scrambling code initialization seed by using values resulting from them modulo the modulus. Specifically, the modulus may be a positive integer, such as a prime number or a power of 2. For example, c.sub.init=n.sub.f.Math.2.sup.a.sup.2+(N.sub.ID.sup.cell mod k).

Embodiment 2

(55) For a first message such as a SIB 1 in a physical downlink shared channel, as shown in FIG. 3, a message sending method in this embodiment of this application includes the following steps.

(56) Step 300: A base station generates a scrambling code according to a first parameter, where the first parameter includes a radio frame number or a value resulting from the radio frame number modulo a first modulus, and the first modulus is a positive integer greater than or equal to 3.

(57) For example, the radio frame number in this embodiment of this application may be a radio frame number in which a start position for sending a first message is located, or the radio frame number may be a radio frame number in which a last location for sending a first message is located, or the like. Cases of a timeslot number, a hyper frame number, and a symbol number are similar to this, and are not described herein.

(58) It should be noted that, in this embodiment of this application, the radio frame number varies with time, and the scrambling code generated by the base station is determined according to the first parameter. The first parameter includes the radio frame number or the value resulting from the radio frame number modulo the first modulus, and the first modulus is a positive integer greater than or equal to 3. Therefore, there are at least three different moments for the determined scrambling code, and scrambling codes generated by the base station at the at least three different moments are different. The first message is scrambled according to the scrambling code. Therefore, an anti-interference capability in transmission of the first message is improved according to this embodiment of this application.

(59) For example, the first message is a SIB 1. In an NB-IoT, radio frame numbers that carry the SIB 1 are separated by an even quantity of radio frame numbers. Therefore, when the first modulus is a positive integer greater than or equal to 3, there are at least three different values for the value resulting from the time-varying radio frame number modulo the first modulus.

(60) Step 310: The base station scrambles a first message according to the scrambling code.

(61) Specifically, the first message may be a complete system message, or may be a part of a complete system message. Alternatively, the first message may be an encoded system message, or may be a part of an encoded system message. It should be noted that, alternatively, the first message may be a system message before encoding, or may be a part of a system message before encoding. For example, when the complete system message is a SIB 1, the first message in this embodiment of this application may be a SIB 1; and specifically, the first message may be an encoded SIB 1, or may be an uncoded SIB 1. Alternatively, the first message may be a part of a SIB1; and specifically, the first message may be a part of an encoded SIB 1, or may be a part of an uncoded SIB 1.

(62) Step 320: The base station sends the scrambled first message to a terminal on a first channel.

(63) In this embodiment of this application, the first channel may be a physical downlink shared channel.

(64) In addition, this embodiment of this application may be applied to a channel in addition to the physical downlink shared channel, for example, a channel such as a PUSCH, a PDCCH, a PUCCH, a PCFICH, a PMCH, or a PRACH. Names of the channels are all provided according to an LTE conventional naming rule, but the channels may have other names in another communications system. For example, the physical downlink shared channel is named an NPDSCH (narrowband physical downlink shared channel) in the NB-IoT. Details are not described herein.

(65) Step 330: The terminal determines the first parameter.

(66) Specifically, before sending the scrambled first message to the terminal, the base station sends a synchronization message to the terminal. The synchronization message may be used to indicate information about the first parameter (or a part of information about the first parameter; for example, when the first parameter includes only a radio frame number in an NB-IoT system, the terminal may use the synchronization message to determine a value resulting from the radio frame number modulo 8). The first parameter is a parameter used as a basis when the base station generates the scrambling code. The scrambling code is a scrambling code used by the base station to scramble the first message. The terminal determines the first parameter according to the synchronization message sent by the base station. Step 330 in which the terminal determines the first parameter may be performed before step 320, or may be performed after step 320. Alternatively, step 330 and step 320 may be simultaneously performed.

(67) Step 340: The terminal receives the scrambled first message on the first channel.

(68) It should be understood that, in an example in which the first channel is a physical downlink shared channel, when the base station sends the scrambled system message on the physical downlink shared channel, the terminal receives the scrambled system message on the physical downlink shared channel.

(69) Step 350: The terminal generates a scrambling code according to the first parameter.

(70) A manner in which the terminal generates the scrambling code according to the first parameter is similar to a manner in which the base station generates the scrambling code according to the first parameter. In this embodiment of this application, the manner in which the base station generates the scrambling code according to the first parameter is described in detail. For the manner in which the terminal generates the scrambling code according to the first parameter, refer to the manner in which the base station generates the scrambling code according to the first parameter in this embodiment of this application.

(71) It should be noted that there is no definite sequence for step 340 and step 330 and for step 340 and step 350; and step 330 is performed before step 350.

(72) Step 360: The terminal descrambles the received scrambled first message according to the scrambling code.

(73) In this embodiment of this application, a value of the first modulus may be 2.sup.n, where n is a positive integer greater than 1. For example, the value of the first modulus may be 4, 8, 16, 32, 64, 128, 256, or 512. Alternatively, the value of the first modulus may be a prime number greater than or equal to 3, such as 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, or 61.

(74) Further, in addition to either of the radio frame number or the value resulting from the radio frame number modulo the first modulus, the first parameter may include at least one of an RNTI (radio network temporary identifier), a timeslot number, a symbol number, a cell identity, or a carrier identifier.

(75) When the first message is a system message, the RNTI may be an SI-RNTI.

(76) For example, the first parameter includes the radio frame number. Because the scrambling code is generated according to the radio frame number, the scrambling code generated according to the first parameter also varies with time, so that an anti-interference capability in sending of the first message is enhanced. In this embodiment of this application, because the first modulus is a positive integer greater than or equal to 3, at least three different values are obtained from different radio frame numbers modulo the first modulus. Therefore, at least three scrambling codes generated according to the first parameter are different, thereby ensuring that the radio frame number can make the generation of the scrambling code initialization seed more randomized.

(77) When the first parameter includes the value resulting from the radio frame number modulo the first modulus, a quantity of bits of the obtained scrambling code is more easily not greater than a preset maximum quantity of bits. When the first modulus is a prime number greater than or equal to 3, a better anti-interference capability in sending of the first message can be achieved by using a feature of the prime number.

(78) For example, a prime number 5 can be divided exactly only by 5 and 1. Therefore, when the first modulus is a prime number, a quantity of different values resulting from different radio frame numbers modulo the first modulus is greater than that obtained when the first modulus is a non-prime number. Therefore, when the first modulus is a prime number, a better anti-interference capability in sending of the first message can be achieved.

(79) In step 300, the base station generates the scrambling code according to the first parameter. Specifically, the scrambling code may be directly generated according to the first parameter. It is assumed that the first parameter includes only the radio frame number, and the scrambling code may be the radio frame number represented by using a binary system. It is assumed that the first parameter includes only the value resulting from the radio frame number modulo the first modulus, and the scrambling code may be a value resulting from the radio frame number represented by using a binary system modulo the first modulus.

(80) In addition, a base station may generate a scrambling code according to a first parameter in two different implementations. One possible implementation is: The base station generates a scrambling code initialization seed according to the first parameter, and then generates the scrambling code according to the scrambling code initialization seed. The first parameter includes only the radio frame number, or the first parameter includes only the value resulting from the radio frame number modulo the first modulus. The other possible implementation includes a same step of generating the scrambling code as the foregoing possible implementation. The base station generates a scrambling code initialization seed according to the first parameter, and then generates the scrambling code according to the scrambling code initialization seed. However, in addition to either of the radio frame number or the value resulting from the radio frame number modulo the first modulus, the first parameter includes at least one of the RNTI, the timeslot number, the symbol number, the cell identity, or the carrier identifier.

(81) Specifically, in Example 1, the first parameter includes only the radio frame number n.sub.f, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f; or the first parameter includes only the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f mod k. It should be noted that, c.sub.init=n.sub.f is used as an example, and linear deformation may also be performed on c.sub.init=n.sub.f. An example in which n.sub.f is represented by using a binary system is used. In this case, when a condition that a sequence length of the scrambling code initialization seed is not greater than a preset threshold is met, c.sub.init=n.sub.f may be deformed into c.sub.init=n.sub.f+N, where N is a preset constant binary sequence; or c.sub.init=n.sub.f may be deformed into c.sub.init=2.sup.n.Math.n.sub.f+N, where n is a quantity of bits occupied by the constant binary sequence N in c.sub.init. Alternatively, deformation similar to that performed on c.sub.init=n.sub.f may be performed when c.sub.init=n.sub.f mod k. Details are not described herein again.

(82) c.sub.init=2.sup.n.Math.n.sub.f+N is used as an example. It is assumed that a length of c.sub.init is 16, n.sub.f=1011 0111, N=1100 0101, and n=8. In this case, in c.sub.init, n.sub.f is higher eight bits, and N is lower eight bits. c.sub.init=1011 0111 1100 0101.

(83) Example 2: The first parameter includes the value resulting from the radio frame number n.sub.f modulo the first modulus k, the radio network temporary identifier n.sub.RNTI, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.1+(n.sub.f mod k).Math.2.sup.b.sup.1+└n.sub.s/2┘.Math.2.sup.c.sup.1+N.sub.ID.sup.cell, where a.sub.1 is a sum of quantities of bits occupied by (n.sub.f mod k), └n.sub.s/2┘, and N.sub.ID.sup.cell in c.sub.init, b.sub.1 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.1 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(84) For example, it is assumed that c.sub.init is a binary sequence that is not greater than 16 bits, n.sub.RNTI=1011, (n.sub.f mod k)=0001, └n.sub.s/2┘=0101, and N.sub.ID.sup.cell=1010. In this case, a.sub.1=12, b.sub.1=8, and c.sub.1=4. Because c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.1+(n.sub.f mod k).Math.2.sup.b.sup.1+└n.sub.s/2┘.Math.2.sup.c.sup.1+N.sub.ID.sup.cell, c.sub.init=1011 0001 0101 1010. That is, n.sub.RNTI occupies highest four bits in c.sub.init, (n.sub.f mod k) occupies higher four bits in c.sub.init, └n.sub.s/2┘ occupies lower four bits in c.sub.init, and N.sub.ID.sup.cell occupies lowest four bits.

(85) It should be noted that, in this embodiment, specific bits respectively occupied by n.sub.RNTI, (n.sub.f mod k), └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init may be interchanged. This is not limited in this application. For example, c.sub.init=n.sub.RNTI+(n.sub.f mod k).Math.2.sup.c.sup.1+└n.sub.s/2┘.Math.2.sup.b.sup.1+N.sub.ID.sup.cell.Math.2.sup.a.sup.1. In this case, if c.sub.init is a binary sequence that is not greater than 16 bits, a.sub.1=12, b.sub.1=8, and c.sub.1=4, n.sub.RNTI occupies lowest four bits in c.sub.init, (n.sub.f mod k) occupies lower four bits in c.sub.init, └n.sub.s/2┘ occupies higher four bits in c.sub.init, and N.sub.ID.sup.cell occupies highest four bits.

(86) Example 3: The first parameter includes the radio frame number n.sub.f, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.2+└n.sub.s/2┘.Math.2.sup.c.sup.2+N.sub.ID.sup.cell, where b.sub.2 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.2 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(87) Example 4: The first parameter includes the value resulting from the radio frame number n.sub.f modulo the first modulus k, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.b.sup.3+└n.sub.s/2┘.Math.2.sup.c.sup.3+c.sub.init=N.sub.ID.sup.cell, where b.sub.3 is a sum of quantities of bits occupied by └n.sub.2/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.3 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(88) Example 5: The first parameter includes the radio network temporary identifier n.sub.RNTI, the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.4+(n.sub.f mod k).Math.2.sup.b.sup.4+N.sub.ID.sup.cell, where a.sub.4 is a sum of quantities of bits occupied by (n.sub.f mod k) and N.sub.ID.sup.cell in c.sub.init, and b.sub.4 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(89) Example 6: The first parameter includes the cell identity N.sub.ID.sup.cell and the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.b.sup.2+N.sub.ID.sup.cell, where b.sub.5 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(90) Example 7: The first parameter includes the radio frame number n.sub.f and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.6+N.sub.ID.sup.cell, where b.sub.6 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(91) Example 8: The first parameter includes at least one of the radio network temporary identifier n.sub.RNTI, the value resulting from the radio frame number n.sub.f modulo the first modulus k, the timeslot number n.sub.s, or the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=R.Math.2.sup.a.sup.7+[(n.sub.f+h)mod k)+w].sup.u.Math.P.Math.2.sup.b.sup.7+H.Math.2.sup.c.sup.7+Q, where R is a function of the radio network temporary identifier, for example, is equal to the radio network temporary identifier n.sub.RNTI, or is equal to 0 (meaning that there is no parameter R in the formula); h is an integer, for example, is equal to 0 or 1; k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; w is an integer, for example, is equal to 0 or 1; u is a non-negative integer, for example, 0, 1, 2, or 3; P is a function of the cell identity and/or the radio frame number, for example, is equal to the cell identity N.sub.ID.sup.cell, or is equal to N.sub.ID.sup.cell.Math.(n.sub.f mod k).sup.v, where v is a positive integer; H is a function of the timeslot number, for example, is equal to the timeslot number n.sub.s, or is equal to 0 (meaning that there is no parameter H in the formula); Q is a function of the cell identity, for example, is equal to the cell identity, or is equal to 0 (meaning that there is no parameter Q in the formula); a.sub.7 is a non-negative integer, for example, is equal to a sum of quantities of bits occupied by [(n.sub.f+h)mod k)+w].sup.u.Math.P, H, and Q in c.sub.init; b.sub.7 is a non-negative integer, for example, is equal to a sum of quantities of bits occupied by H and Q in c.sub.init; and c.sub.7 is a non-negative integer, for example, is equal to a quantity of bits occupied by Q in c.sub.init.

(92) It should be noted that Example 3 to Example 8 are similar to Example 2. In this embodiment of this application, higher bits and lower bits in the bits occupied in c.sub.init by variables included in the first parameter may be interchanged. Example 1 to Example 8 are merely examples for describing the technical solution of this embodiment of this application, and are not intended to limit the technical solution of this embodiment of this application.

(93) It should be noted that the first parameter may further include at least one of the symbol number, the hyper frame number, or the carrier identifier. In this embodiment of this application, the RNTI, the timeslot number, the symbol number, the hyper frame number, the cell identity, the carrier identifier, and the like may all participate in the generation of the scrambling code initialization seed by using values resulting from them modulo the modulus. Specifically, the modulus may be a prime number or a power of 2. For example, the first parameter includes the radio frame number n.sub.f and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.6+N.sub.ID.sup.cell mod k, where b.sub.6 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(94) In a possible implementation of this embodiment of this application, the base station sends, to the terminal, indication information used to indicate a manner of scrambling the first channel/first information.

(95) Specifically, that the base station sends, to the terminal, indication information used to indicate a manner of scrambling the first channel/first information includes: The indication information may be used to indicate a manner of determining a scrambling code initialization seed of the first channel/first information and/or a scrambling code initialization method.

(96) Specifically, the scrambling code initialization method includes at least one of a scrambling code length or a scrambling code initialization frequency/period.

(97) The indication information may be located in a system message (a MIB or a SIB), and be sent by the base station to the terminal by using a PBCH or a PDSCH.

(98) For example, the first message is a system message such as a SIB 1, and the first channel is a PDSCH. The indication information may be located in a system message MIB and be transmitted in a PBCH.

(99) For example, the indication information may include two binary values 0 and 1, and different values of the indication information may be corresponding to different manners of scrambling the first channel/first information. For example, 0 indicates a method 1 for determining a scrambling code initialization seed, and 1 indicates a method 2 for determining a scrambling code initialization seed.

(100) For example, the indication information may include four binary values 00, 01, 10, and 11 that may be respectively corresponding to M manners of scrambling the first channel/first information, for example, respectively corresponding to M methods for determining a scrambling code initialization seed of the first channel/first information. A value range of M is {1, 2, 3, 4}. When M<4, at least one of four states 00, 01, 10, or 11 may be selectively used.

(101) In the foregoing example, the indication information may include another quantity of values, and details are not described herein.

(102) According to a same inventive concept, the embodiments of the present invention further provide a base station shown in FIG. 4a, a terminal shown in FIG. 5a, and a communications system shown in FIG. 6. A method corresponding to the base station shown in FIG. 4a, the terminal shown in FIG. 5a, and the communications system shown in FIG. 6 is the message transmission method shown in FIG. 1 in the embodiment of this application. Therefore, in the embodiments of this application, for implementations of the base station shown in FIG. 4a, the terminal shown in FIG. 5a, and the communications system shown in FIG. 6, refer to the implementation of the method shown in FIG. 1. No repeated description is provided.

(103) As shown in FIG. 4a, a base station 400a in an embodiment of this application includes a processing module 410a and a sending module 420a. The processing module 410a is configured to: generate a scrambling code according to a first time parameter, and scramble a system message according to the scrambling code. The sending module 420a is configured to send, to a terminal on a physical broadcast channel, the system message scrambled by the processing module 410a.

(104) In a possible implementation, the first time parameter is a function of at least one of a radio frame number, a timeslot number, a hyper frame number, or a symbol number.

(105) In a possible implementation, the first time parameter is any one of a radio frame number, a timeslot number, a hyper frame number, and a symbol number.

(106) Alternatively, the first time parameter is a value resulting from any one of a radio frame number, a timeslot number, a hyper frame number, and a symbol number modulo a first modulus, where the first modulus is a positive integer.

(107) In a possible implementation, the first modulus is 2.sup.n, where n is a positive integer that is not equal to 3; or the first modulus is 8; or the first modulus is a prime number.

(108) A possible implementation in which the processing module 410a generates the scrambling code according to the first time parameter is: generating a scrambling code initialization seed according to the first time parameter and a first variable group, and generating the scrambling code according to the scrambling code initialization seed, where the first variable group includes at least one of a cell identity, a radio network temporary identifier RNTI, or a carrier identifier.

(109) Another possible implementation in which the processing module 410a generates the scrambling code according to the first time parameter is: generating a scrambling code initialization seed according to the first time parameter, and generating the scrambling code according to the scrambling code initialization seed.

(110) This embodiment of this application further provides several possible implementations in which the base station generates the scrambling code initialization seed according to the first time parameter.

(111) The first time parameter is the radio frame number n.sub.f, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=n.sub.f; or the first time parameter is a value resulting from the radio frame number n.sub.f modulo the first modulus k, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=n.sub.f mod k, where k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; or the first time parameter is the radio frame number n.sub.f, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(n.sub.f.Math.2.sup.a.sup.1)+N.sub.ID.sup.cell, or c.sub.init=(N.sub.ID.sup.cell.Math.2.sup.b.sup.1)+n.sub.f, where a.sub.1 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init, and b.sub.1 is a quantity of bits occupied by n.sub.f in c.sub.init; or the first time parameter is a value resulting from the radio frame number n.sub.f modulo the first modulus k, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.a.sup.2+N.sub.ID.sup.cell, or c.sub.init=(n.sub.f mod k).Math.2.sup.a.sup.2+N.sub.ID.sup.cell, where k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; a.sub.2 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; and b.sub.2 is a quantity of bits occupied by (n.sub.f mod k) in c.sub.init.

(112) It should be noted that, in this embodiment of this application, the processing module 410a may be implemented by a processor, and the sending module 420a may be implemented by a transceiver. As shown in FIG. 4b, a base station 400b may include a processor 410b, a transceiver 420b, and a memory 430b. The memory 430b may be configured to store a program/code pre-installed when the base station 400b is delivered from a factory, or may store code executed by the processor 410b, or the like.

(113) The processor 410b may be a general-purpose CPU (central processing unit), a microprocessor, an ASIC (application-specific integrated circuit), or one or more integrated circuits, and is configured to perform a related operation, so as to implement the technical solution provided in this embodiment of this application.

(114) It should be noted that although only the processor 410b, the transceiver 420b, and the memory 430b are shown in the base station 400b shown in FIG. 4b, in a specific implementation process, persons skilled in the art should understand that the base station 400b further includes another device required for implementing normal running. In addition, persons skilled in the art should understand that, according to a specific requirement, the base station 400b may further include a hardware device that implements another additional function. In addition, persons skilled in the art should understand that the base station 400b may include only devices or modules required for implementing this embodiment of this application, but not necessarily include all the devices shown in FIG. 4b.

(115) Persons of ordinary skill in the art may understand that all or some of the processes of the methods in the embodiments may be implemented by a computer program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program is executed, the processes of the methods in the embodiments may be included. The foregoing storage medium may be a magnetic disk, an optical disc, a ROM (read-only memory), a RAM (random access memory), or the like.

(116) As shown in FIG. 5a, a terminal 500a in an embodiment of this application includes a processing module 510a and a receiving module 520a. The processing module 510a is configured to determine a first time parameter. The receiving module 520a is configured to receive a scrambled system message on a physical broadcast channel. The processing module 510a is further configured to: generate a scrambling code according to the first time parameter; and descramble, according to the scrambling code, the scrambled system message received by the receiving module 520a.

(117) In a possible implementation, the first time parameter is a function of at least one of a radio frame number, a timeslot number, a hyper frame number, or a symbol number.

(118) In a possible implementation, the first time parameter is any one of a radio frame number, a timeslot number, a hyper frame number, and a symbol number.

(119) Alternatively, the first time parameter is a value resulting from any one of a radio frame number, a timeslot number, a hyper frame number, and a symbol number modulo a first modulus, where the first modulus is a positive integer.

(120) In a possible implementation, the first modulus is 2.sup.n, where n is a positive integer that is not equal to 3; or the first modulus is 8; or the first modulus is a prime number.

(121) A possible implementation in which the processing module 510a generates the scrambling code according to the first time parameter is: generating a scrambling code initialization seed according to the first time parameter and a first variable group, and generating the scrambling code according to the scrambling code initialization seed, where the first variable group includes at least one of a cell identity, a radio network temporary identifier RNTI, or a carrier identifier.

(122) Another possible implementation in which the processing module 510a generates the scrambling code according to the first time parameter is: generating a scrambling code initialization seed according to the first time parameter, and generating the scrambling code according to the scrambling code initialization seed.

(123) This embodiment of this application further provides several possible implementations in which the terminal generates the scrambling code initialization seed according to the first time parameter.

(124) The first time parameter is the radio frame number n.sub.f, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=n.sub.f; or the first time parameter is a value resulting from the radio frame number n.sub.f modulo the first modulus k, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=n.sub.f mod k, where k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; or the first time parameter is the radio frame number n.sub.f, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(n.sub.f.Math.2.sup.a.sup.1)+N.sub.ID.sup.cell, or c.sub.init=(N.sub.ID.sup.cell.Math.2.sup.b.sup.1)+n.sub.f, where a.sub.1 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init, and b.sub.1 is a quantity of bits occupied by n.sub.f in c.sub.init; or the first time parameter is a value resulting from the radio frame number n.sub.f modulo the first modulus k, the first variable group includes the cell identity N.sub.ID.sup.cell, and the initialization scrambling code seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.a.sup.2+N.sub.ID.sup.cell, or c.sub.init=N.sub.ID.sup.cell.Math.2.sup.b.sup.2+(n.sub.f mod k), where k=8, k is a prime number, or k is a positive integer that is not 8 or a prime number; a.sub.2 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; and b.sub.2 is a quantity of bits occupied by (n.sub.f mod k) in c.sub.init.

(125) It should be noted that, in this embodiment of this application, the processing module 510a may be implemented by a processor, and the receiving module 520a may be implemented by a transceiver. As shown in FIG. 5b, a terminal 500b may include a processor 510b, a transceiver 520b, and a memory 530b. The memory 530b may be configured to store a program/code pre-installed when the terminal 500b is delivered from a factory, or may store code executed by the processor 510b, or the like.

(126) The processor 510b may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits, and is configured to perform a related operation, so as to implement the technical solution provided in this embodiment of this application.

(127) It should be noted that although only the processor 510b, the transceiver 520b, and the memory 530b are shown in the terminal 500b shown in FIG. 5b, in a specific implementation process, persons skilled in the art should understand that the terminal 500b further includes another device required for implementing normal running. In addition, persons skilled in the art should understand that, according to a specific requirement, the terminal 500b may further include a hardware device that implements another additional function. In addition, persons skilled in the art should understand that the terminal 500b may include only devices or modules required for implementing this embodiment of this application, but not necessarily include all the devices shown in FIG. 5b.

(128) Persons of ordinary skill in the art may understand that all or some of the processes of the methods in the embodiments may be implemented by a computer program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program is executed, the processes of the methods in the embodiments may be included. The foregoing storage medium may be a magnetic disk, an optical disk, a ROM, a RAM, or the like.

(129) As shown in FIG. 6, a communications system 600 in an embodiment of this application includes the base station 400a shown in FIG. 4a and the terminal 500a shown in FIG. 5a.

(130) According to a same inventive concept, the embodiments of the present invention further provide a base station shown in FIG. 7a, a terminal shown in FIG. 8a, and a communications system shown in FIG. 9. A method corresponding to the base station shown in FIG. 7a, the terminal shown in FIG. 8a, and the communications system shown in FIG. 9 is the message transmission method shown in FIG. 3 in the embodiment of this application. Therefore, in the embodiments of this application, for implementations of the base station shown in FIG. 7a, the terminal shown in FIG. 8a, and the communications system shown in FIG. 9, refer to the implementation of the method shown in FIG. 3. No repeated description is provided.

(131) As shown in FIG. 7a, a base station 700a in an embodiment of this application includes a processing module 710a and a sending module 720a. The processing module 710a is configured to: generate a scrambling code according to a first parameter, and scramble a first message according to the scrambling code. The first parameter includes a radio frame number or a value resulting from the radio frame number modulo a first modulus, and the first modulus is a positive integer greater than or equal to 3. The sending module 720a is configured to send the scrambled first message to a terminal on a first channel.

(132) In a possible implementation, the first message is a system message, or the first message is a part of a system message; or the first message is an encoded system message, or the first message is a part of an encoded system message. The first channel is a physical downlink shared channel or a physical broadcast channel.

(133) In a possible implementation, in addition to the radio frame number or the value resulting from the radio frame number modulo the first modulus, the first parameter includes at least one of a radio network temporary identifier RNTI, a timeslot number, a symbol number, a cell identity, or a carrier identifier.

(134) In a possible implementation, the first modulus is 2.sup.n, where n is a positive integer greater than 1; or the first modulus is a prime number greater than or equal to 3.

(135) A possible implementation in which the processing module 710a generates the scrambling code according to the first parameter is: generating a scrambling code initialization seed according to the first parameter, and generating the scrambling code according to the scrambling code initialization seed.

(136) This embodiment of this application further provides several possible implementations in which the base station generates the scrambling code initialization seed according to the first parameter.

(137) The first parameter includes the value resulting from the radio frame number n.sub.f modulo the first modulus k, the radio network temporary identifier n.sub.RNTI, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.1+(n.sub.f mod k).Math.2.sup.b.sup.1+└n.sub.s/2┘.Math.2.sup.c.sup.1+N.sub.ID.sup.cell, where a.sub.1 is a sum of quantities of bits occupied by (n.sub.f mod k), └n.sub.s/2┘, and N.sub.ID.sup.cell in c.sub.init, b.sub.1 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.1 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the radio frame number n.sub.f, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.2+└n.sub.s/2┘.Math.2.sup.c.sup.2+N.sub.ID.sup.cell, where b.sub.2 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.2 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the value resulting from the radio frame number n.sub.f modulo the first modulus k, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.b.sup.3+└n.sub.s/2┘.Math.2.sup.c.sup.3+N.sub.ID.sup.cell, where b.sub.3 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.3 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the radio network temporary identifier n.sub.RNTI, the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.4+(n.sub.f mod k).Math.2.sup.b.sup.4+N.sub.ID.sup.cell, where a.sub.4 is a sum of quantities of bits occupied by (n.sub.f mod k) and N.sub.ID.sup.cell in c.sub.init, and b.sub.4 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the cell identity N.sub.ID.sup.cell and the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.b.sup.3+N.sub.ID.sup.cell, where b.sub.5 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the radio frame number n.sub.f and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.6+N.sub.ID.sup.cell, where b.sub.6 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(138) It should be noted that, in this embodiment of this application, the processing module 710a may be implemented by a processor, and the sending module 720a may be implemented by a transceiver. As shown in FIG. 7b, a base station 700b may include a processor 710b, a transceiver 720b, and a memory 730b. The memory 730b may be configured to store a program/code pre-installed when the base station 700b is delivered from a factory, or may store code executed by the processor 710b, or the like.

(139) The processor 710b may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits, and is configured to perform a related operation, so as to implement the technical solution provided in this embodiment of this application.

(140) It should be noted that although only the processor 710b, the transceiver 720b, and the memory 730b are shown in the base station 700b shown in FIG. 7b, in a specific implementation process, persons skilled in the art should understand that the base station 700b further includes another device required for implementing normal running. In addition, persons skilled in the art should understand that, according to a specific requirement, the base station 700b may further include a hardware device that implements another additional function. In addition, persons skilled in the art should understand that the base station 700b may include only devices or modules required for implementing this embodiment of this application, but not necessarily include all the devices shown in FIG. 7b.

(141) Persons of ordinary skill in the art may understand that all or some of the processes of the methods in the embodiments may be implemented by a computer program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program is executed, the processes of the methods in the embodiments may be included. The foregoing storage medium may be a magnetic disk, an optical disk, a ROM, a RAM, or the like.

(142) As shown in FIG. 8a, a terminal 800a in an embodiment of this application includes a processing module 810a and a receiving module 820a. The processing module 810a is configured to determine a first parameter. The first parameter includes a radio frame number or a value resulting from the radio frame number modulo a first modulus, and the first modulus is a positive integer greater than or equal to 3. The receiving module 820a is configured to receive a scrambled first message on a first channel. The processing module 810a is further configured to: generate a scrambling code according to the first parameter; and descramble, according to the scrambling code, the scrambled first message received by the receiving module 820a.

(143) In a possible implementation, the first message is a system message, or the first message is a part of a system message; or the first message is an encoded system message, or the first message is a part of an encoded system message. The first channel is a physical downlink shared channel or a physical broadcast channel.

(144) In a possible implementation, in addition to the radio frame number or the value resulting from the radio frame number modulo the first modulus, the first parameter includes at least one of a radio network temporary identifier RNTI, a timeslot number, a symbol number, a cell identity, or a carrier identifier.

(145) In a possible implementation, the first modulus is 2.sup.n, where n is a positive integer greater than 1; or the first modulus is a prime number greater than or equal to 3.

(146) A possible implementation in which the processing module 810a generates the scrambling code according to the first parameter is: generating a scrambling code initialization seed according to the first parameter, and generating the scrambling code according to the scrambling code initialization seed.

(147) This embodiment of this application further provides several possible implementations in which the processing module 810a generates the scrambling code initialization seed according to the first time parameter.

(148) The first parameter includes the value resulting from the radio frame number n.sub.f modulo the first modulus k, the radio network temporary identifier n.sub.RNTI, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.1+(n.sub.f mod k).Math.2.sup.b.sup.1+└n.sub.s/2┘.Math.2.sup.c.sup.1+N.sub.ID.sup.cell, where a.sub.1 is a sum of quantities of bits occupied by (n.sub.f mod k), └n.sub.s/2┘, and N.sub.ID.sup.cell in c.sub.init, b.sub.1 is a sum of quantities of bits occupied by └n.sub.2/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.1 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the radio frame number n.sub.f, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.2+└n.sub.s/2┘.Math.2.sup.c.sup.2+N.sub.ID.sup.cell, where b.sub.2 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.2 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the value resulting from the radio frame number n.sub.f modulo the first modulus k, the timeslot number n.sub.s, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.b.sup.3+└n.sub.s/2┘.Math.2.sup.c.sup.3+N.sub.ID.sup.cell, where b.sub.3 is a sum of quantities of bits occupied by └n.sub.s/2┘ and N.sub.ID.sup.cell in c.sub.init, and c.sub.3 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the radio network temporary identifier n.sub.RNTI, the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.RNTI.Math.2.sup.a.sup.4+(n.sub.f mod k).Math.2.sup.b.sup.4+N.sub.ID.sup.cell, where b.sub.4 is a sum of quantities of bits occupied by (n.sub.f mod k) and N.sub.ID.sup.cell in c.sub.init, and b.sub.4 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the cell identity N.sub.ID.sup.cell and the value resulting from the radio frame number n.sub.f modulo the first modulus k, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=(n.sub.f mod k).Math.2.sup.b.sup.5+N.sub.ID.sup.cell, where b.sub.5 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init; or the first parameter includes the radio frame number n.sub.f and the cell identity N.sub.ID.sup.cell, and the scrambling code initialization seed c.sub.init meets the following expression: c.sub.init=n.sub.f.Math.2.sup.b.sup.6+N.sub.ID.sup.cell, where b.sub.6 is a quantity of bits occupied by N.sub.ID.sup.cell in c.sub.init.

(149) It should be noted that, in this embodiment of this application, the processing module 810a may be implemented by a processor, and the receiving module 820a may be implemented by a transceiver. As shown in FIG. 8b, a terminal 800b may include a processor 810b, a transceiver 820b, and a memory 830b. The memory 830b may be configured to store a program/code pre-installed when the terminal 800b is delivered from a factory, or may store code executed by the processor 810b, or the like.

(150) The processor 810b may be a general-purpose CPU, a microprocessor, an ASIC, or one or more integrated circuits, and is configured to perform a related operation, so as to implement the technical solution provided in this embodiment of this application.

(151) It should be noted that although only the processor 810b, the transceiver 820b, and the memory 830b are shown in the terminal 800b shown in FIG. 8b, in a specific implementation process, persons skilled in the art should understand that the terminal 800b further includes another device required for implementing normal running. In addition, persons skilled in the art should understand that, according to a specific requirement, the terminal 800b may further include a hardware device that implements another additional function. In addition, persons skilled in the art should understand that the terminal 800b may include only devices or modules required for implementing this embodiment of this application, but not necessarily include all the devices shown in FIG. 8b.

(152) Persons of ordinary skill in the art may understand that all or some of the processes of the methods in the embodiments may be implemented by a computer program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program is executed, the processes of the methods in the embodiments may be included. The foregoing storage medium may be a magnetic disk, an optical disk, a ROM, a RAM, or the like.

(153) As shown in FIG. 9, a communications system 900 in an embodiment of this application includes the base station 700a shown in FIG. 7a and the terminal 800a shown in FIG. 8a.

(154) In conclusion, in the embodiments of this application, a base station generates a scrambling code according to a first time parameter, then scrambles a system message according to the scrambling code, and finally sends the scrambled system message to a terminal on a physical broadcast channel. In this technical solution, because the first time parameter has different values at at least two different moments, scrambling codes determined at the at least two corresponding different moments are different. Therefore, a possibility at which the base station uses a same scrambling code to scramble a same system message repeatedly in a time period is reduced, so that an anti-interference capability in system message transmission is improved.

(155) Persons skilled in the art should understand that the embodiments of this application may be provided as a method, a system, or a computer program product. Therefore, the embodiments of this application may use a form of hardware only embodiments, software only embodiments, or embodiments with a combination of software and hardware. In addition, the embodiments of this application may use a form of a computer program product that is implemented on one or more computer usable storage media (including but not limited to a magnetic disk memory, a CD-ROM, an optical memory, and the like) that include computer usable program code.

(156) The embodiments of this application have been described with reference to the flowcharts and/or block diagrams of the method, the device (system), and the computer program product according to the embodiments of this application. It should be understood that computer program instructions may be used to implement each process and/or each block in the flowcharts and/or the block diagrams, and a combination of a process and/or a block in the flowcharts and/or the block diagrams. These computer program instructions may be provided for a general-purpose computer, a dedicated computer, an embedded processor, or a processor of any other programmable data processing device to generate a machine, so that the instructions executed by a computer or a processor of any other programmable data processing device generate an apparatus for implementing a specified function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

(157) These computer program instructions may be stored in a computer readable memory that can instruct the computer or any other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory generate an artifact that includes an instruction apparatus. The instruction apparatus implements a specified function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

(158) These computer program instructions may also be loaded onto a computer or another programmable data processing device, so that a series of operations and steps are performed on the computer or the another programmable device, thereby generating computer-implemented processing. Therefore, the instructions executed on the computer or the another programmable device provide steps for implementing a specified function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.

(159) Persons skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of this application. This application is intended to cover these modifications and variations provided that they fall within the scope of protection defined by the following claims and their equivalent technologies.