Establishing additional reverse link carriers in multi-carrier wireless systems

Abstract

A method and apparatus for reliably and quickly establishing multiple reverse links in multi-carrier wireless networks is provided. Signaling channels are established on an existing forward link in order to transmit reverse link power control bits and the acknowledgment indications.

Claims

1. A method of receiving control information at a mobile station (MS) in a multi-carrier wireless communication system, the method comprising: establishing multiple forward link carriers between the MS and a base station (BS), wherein each of the multiple forward link carriers is separated from each other in a frequency domain; establishing multiple reverse link carriers between the MS and the BS, wherein each of the multiple reverse link carriers is associated with a respective one of the multiple forward link carriers, and separated from each other in the frequency domain; receiving first control information for a first reverse link carrier of the multiple reverse link carriers; and receiving second control information for a second reverse link carrier of the multiple reverse link carriers, the second control information for the second reverse link carrier being different from the first control information for the first reverse link carrier, wherein the first control information for the first reverse link carrier and the second control information for the second reverse link carrier are received from the BS via a common forward link carrier of the multiple forward link carriers between the MS and the BS.

2. The method of claim 1, wherein the first control information and the second control information comprises power control information.

3. A method of transmitting control information at a base station (BS) in a multi-carrier wireless communication system, the method comprising: establishing multiple forward link carriers between a mobile station (MS) and the base station (BS), wherein each of the multiple forward link carriers is separated from each other in a frequency domain; establishing multiple reverse link carriers between the MS and the BS, wherein each of the multiple reverse link carriers is associated with a respective one of the multiple forward link carriers, and separated from each other in the frequency domain; transmitting first control information for a first reverse link carrier of the multiple reverse link carriers; and transmitting second control information for a second reverse link carrier of the multiple reverse link carriers, the second control information for the second reverse link carrier being different from the first control information for the first reverse link carrier, wherein the first control information for the first reverse link carrier and the second control information for the second reverse link carrier are transmitted to the MS via a common forward link carrier of the multiple forward link carriers between the MS and the BS.

4. The method of claim 3, wherein the first control information and the second control information comprises power control information.

5. A mobile station (MS) used in a multi-carrier wireless communication system, the MS comprising: a radio frequency unit; and a processor configured to: establish multiple forward link carriers between the MS and a base station (BS), wherein each of the multiple forward link carriers is separated from each other in a frequency domain; establish multiple reverse link carriers between the MS and the BS, wherein each of the multiple reverse link carriers is associated with a respective one of the multiple forward link carriers, and separated from each other in the frequency domain; receive first control information for a first reverse link carrier of the multiple reverse link carriers; and receive second control information for a second reverse link carrier of the multiple reverse link carriers, the second control information for the second reverse link carrier being different from the first control information for the first reverse link carrier, wherein the first control information for the first reverse link carrier and the second control information for the second reverse link carrier are received from the BS via a common forward link carrier of the multiple forward link carriers between the MS and the BS.

6. The MS of claim 5, wherein the first control information and the second control information comprises power control information.

7. A base station (BS) used in a multi-carrier wireless communication system, the BS comprising: a radio frequency unit; and a processor configured to: establish multiple forward link carriers between a mobile station (MS) and the base station (BS), wherein each of the multiple forward link carriers is separated from each other in a frequency domain; establish multiple reverse link carriers between the MS and the BS, wherein each of the multiple reverse link carriers is associated with a respective one of the multiple forward link carriers, and separated from each other in the frequency domain; transmit first control information for a first reverse link carrier of the multiple reverse link carriers; and transmit second control information for a second reverse link carrier of the multiple reverse link carriers, the second control information for the second reverse link carrier being different from the first control information for the first reverse link carrier, wherein the first control information for the first reverse link carrier and the second control information for the second reverse link carrier are transmitted to the MS via a common forward link carrier of the multiple forward link carriers between the MS and the BS.

8. The BS of claim 7, wherein the first control information and the second control information comprises power control information.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. Features, elements, and aspects of the invention that are referenced by the same numerals in different figures represent the same, equivalent, or similar features, elements, or aspects in accordance with one or more embodiments.

(2) FIG. 1 illustrates wireless communication network architecture.

(3) FIG. 2A illustrates a CDMA spreading and de-spreading process.

(4) FIG. 2B illustrates a CDMA spreading and de-spreading process using multiple spreading sequences.

(5) FIG. 3 illustrates a data link protocol architecture layer for a cdma2000 wireless network.

(6) FIG. 4 illustrates cdma2000 call processing.

(7) FIG. 5 illustrates the cdma2000 initialization state.

(8) FIG. 6 illustrates the cdma2000 system access state.

(9) FIG. 7 illustrates a comparison of cdma2000 for 1× and 1×EV-DO.

(10) FIG. 8 illustrates a network architecture layer for a 1×EV-DO wireless network.

(11) FIG. 9 illustrates 1×EV-DO default protocol architecture.

(12) FIG. 10 illustrates 1×EV-DO non-default protocol architecture.

(13) FIG. 11 illustrates 1×EV-DO session establishment.

(14) FIG. 12 illustrates 1×EV-DO connection layer protocols.

(15) FIG. 13 illustrates 1×EV-DO ACK/NAK operation.

(16) FIG. 14 illustrates the 1×EV-DO reverse link ACK channel.

(17) FIGS. 15A and 15B illustrate a method for establishing multiple reverse links according to one embodiment of the present invention.

(18) FIGS. 16A and 16B illustrate a method for establishing multiple reverse links according to another embodiment of the present invention according to one embodiment of the present invention.

(19) FIG. 17 illustrates a block diagram of a mobile station or access terminal according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(20) The present invention relates to a method and apparatus for reliably and quickly establishing multiple reverse links in multi-carrier wireless networks. Although the present invention is illustrated with respect to a mobile terminal, it is contemplated that the present invention may be utilized anytime it is desired to establish multiple reverse links for communication devices in multi-carrier wireless networks.

(21) According to the methods of the present invention, a feedback channel is first established on the forward link (FL). Specifically, signaling channels are established on the FL in order to transmit reverse link (RL) power control (RPC) bits and the RL ACK/NAK indications.

(22) The establishment of a feedback channel on the FL will allow the AN 6 to facilitate the setup of the RL in a reliable and quick fashion. In multi-carrier systems where there already exists at least one RL in operation, the process is more efficient.

(23) Once the feedback channel has been established, the AT 2 must determine the initial transmission power on the new RL carrier. Information available at the AT 2 or some subset of the information may be used. For example, RL load via the reverse activity bit (RAB), which is set by the AN 6, and correlation, estimates between existing reverse links and the new RL may be utilized.

(24) The present invention provides a method to establish the feedback channel on the FL. The feedback channel can be a dedicated FL channel used to support the new RL channel.

(25) Although the present invention is described with regard to a two-carrier system with two frequencies, f1 and f2, it will be understood that the present invention may be applied to any multi-carrier system. The methods of the present invention assume that the FL (f1) and RL (f1) have already been established, as in a single-carrier system. The methods of the present invention are directed to establishing the RL on the new carrier f2.

(26) First, the AT 2 measures channel quality information (CQI) or data rate control (DRC) information over FL (f2) using, for example, the pilot signal (f2). The CQI (f2) information is then transmitted to the AN 6 over the existing RL (f1).

(27) Upon reception of the CQI (f2), the AN 6 initiates power control of the RL channel. The AN 6 begins monitoring RL (f2) for the RL signal of the AT 2, such as RL pilot (f2), and estimates its SNR. As in conventional methods, this measured pilot SNR is compared against a threshold SNR, commonly referred to as the inner loop power control set point, which is the reception power level desired by the AN 6 and may be changed according to an error rate.

(28) The inner loop power control set point may be determined in a number of ways. For example, a default value could be used initially that is sufficient to detect the RRI.

(29) Outer loop power control can begin once the null-rate RRI is detected. Outer loop power control may be initiated once the set point is reached and a first DOWN command is sent. Furthermore, Outer loop power control may be initiated once the first RTC is decoded.

(30) The AN 6 transmits the RPC (f2) commands to the AT 2 on the new carrier FL (f2). The power allocated to the RPC (f2), and later the ACK channel, is determined by CQI (f2).

(31) It should be pointed out that measurement of the channel quality information (CQI) or data rate control (DRC) information over FL (f2) by the AT 2 can be pre-empted if the RPC (f2) commands are sent over FL (f1). Furthermore the measurement may be pre-empted if FL (f2) is not active in any way. Moreover, even if FL (f2) is active, a DRC (f2) should already be working and the measurement may still be pre-empted.

(32) Once the RPC (f2) feedback channel has been established, the AT 2 can then begin transmission of the RL (f2) at an initial transmission power (f2). The signal could be, for example, the reverse rate indicator (RRI) channel. The power of the RL signal, such as the Pilot, can then be immediately power controlled by the RPC (f2) feedback.

(33) The AT 2 knows when to begin RTC transmission based on a response from the AN 6. The AN 6 may send an upper layer RTC ACK message over the existing FL already established, such as on primary or even a new FL carrier. The AN 6 may send a PHY layer ACK.

(34) The PHY layer ACK may be triggered by monitoring the RRI, which could be defined as the null-rate for initial transmission until the ACK is sent, or preferably by monitoring the pilot power and when the first DOWN command of RPC is sent. Errors in any of the detections, such as RRI detection and ACK/NAK detection, must be checked.

(35) The methods of the present invention provide for improved reliability and speed of the new RL carrier set up.

(36) If the ACK channel is not used as described, then the AN 6 and AT 2 may use the additional feedback channel, such as the ACK/NAK channel (f2). Initially, if the AT 2 receives a NAK, the AT can decide to boost the transmission power further.

(37) For example, if a NAK (f2) is received, the AT 2 increases power using a larger step size, such as 2 dB. This operation could stop after the AT 2 receives the first ACK. Alternately, the RPC (f2) commands can initially use a larger step size, such as 2 dB, until the first ACK is received by the AT 2 from the AN 6

(38) The AT 2 could initially send only the RL pilot (f2). Regular operation could start once the first RPC (f2) DOWN command is received.

(39) The AT 2 could send a “pseudo-probe” over the RL traffic on all RL interlaces, or parallel ARQ channels. For N×EV-DO, this pseudo-probe could be the RRI. This would help establish the set point more quickly.

(40) Before beginning packet transmissions, it may be ensured that the RTC is stable. The stable state may be defined as when the first DOWN command and/or first ACK is sent. The ACK could also be used, at least initially, to indicate the stable state.

(41) According to the present invention a RPC channel is established first before transmission on the new RL. An RPC channel of new RL is established on the paired FL carrier. Alternately, an RPC channel of new RL may be established on FL anchor carrier.

(42) FIGS. 15A and 15B illustrate a first method according to the present invention. FIGS. 16A and 16B illustrate a second method according to the present invention.

(43) As illustrated in FIGS. 15A and 15B, the AT 2 measures channel quality information of the new FL_b. DRC_b is then transmitted to the AN 6 over the existing RL_a. The AN 6 then transmits the RPC_b commands to the AT 2 on the new carrier FL_b.

(44) As illustrated in FIGS. 16A and 16B, the AN 6 transmits the RPC_b commands to the AT 2 on the existing carrier FL_a. There is no need to measure channel quality information of the new FL_b or to transmit DRC_b to the AN 6.

(45) As illustrated in FIGS. 15A and 15B and 16A and 16B, once the RPC_b feedback channel has been established, the AT 2 can then begin transmission of the RL_b pilot and RRI at an initial transmission power (b). The 1st down command by rpc_b or RRI on RL_b is then correctly detected. The AN 6 may use the RRI error to adjust the outer loop set point for rpc_b. Either PHY ACK on FL_b or RTCACK is used to indicate acquisition of RL_b to the AT 2.

(46) FIG. 17 illustrates a block diagram of a mobile station (MS) or access terminal 100 according to one embodiment of the present invention. The AT 100 includes a processor (or digital signal processor) 110, RF module 135, power management module 105, antenna 140, battery 155, display 115, keypad 120, memory 130, SIM card 125 (which may be optional), speaker 145 and microphone 150.

(47) A user enters instructional information, such as a telephone number, for example, by pushing the buttons of a keypad 120 or by voice activation using the microphone 150. The microprocessor 110 receives and processes the instructional information to perform the appropriate function, such as to dial the telephone number. Operational data may be retrieved from the Subscriber Identity Module (SIM) card 125 or the memory module 130 to perform the function. Furthermore, the processor 110 may display the instructional and operational information on the display 115 for the user's reference and convenience.

(48) The processor 110 issues instructional information to the RF module 135, to initiate communication, for example, by transmitting radio signals comprising voice communication data. The RF module 135 includes a receiver and a transmitter to receive and transmit radio signals. An antenna 140 facilitates the transmission and reception of radio signals. Upon receiving radio signals, the RF module 135 may forward and convert the signals to baseband frequency for processing by the processor 110. The processed signals would be transformed into audible or readable information outputted via the speaker 145, for example. The processor 110 also includes the protocols and functions necessary to perform the various processes described herein with regard to cdma2000 or 1×EV-DO systems.

(49) The processor 110 is adapted to perform the methods disclosed herein for establishing multiple reverse links in multi-carrier wireless networks. The processor generates and controls the RF module 135 to transmit DRC_b and RPC_b and to receive FL_a and FL_b as illustrated in FIGS. 15A, 15B, 16A and 16B.

(50) Although the present invention is described with reference to cdma2000, 1×EV-DO and cdma2000 N×EV-DO, it may also be applied to other applicable communication systems.

(51) As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.

(52) The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structure described herein as performing the recited function and not only structural equivalents but also equivalent structures.