Advanced backhaul services
11303322 · 2022-04-12
Assignee
Inventors
Cpc classification
H04B1/0475
ELECTRICITY
H04B7/0632
ELECTRICITY
International classification
Abstract
“Tiered” groups of devices (tiered service radios) and/or licenses associated with the devices or users so as to provide a hieratical set of interference protection mechanisms for members of each tier of service are disclosed. Point-to-point and point-to-multipoint data links for any communication application, including wireless backhaul applications, are also disclosed. Exemplary systems, devices, and methods disclosed herein allow for the efficient operation of such a tiered service. Interference protection among tiered service devices belonging to one or more tiers of the service, from other devices within the same tier of service, or devices of other tiers of service, is disclosed. Identification of other devices of the same or differing tiers of service, and interference mitigation between other tiered service devices based upon intercommunication between the devices, and/or via a central registry database, are also disclosed.
Claims
1. A method comprising: utilizing signature radio signals, for providing network optimization control intercommunication between a first backhaul radio and one or more other backhaul radios and providing for determination of presence and operating parameters of the one or more other backhaul radios; performing a progressive interference procedure; adjusting at least one network parameter of the first backhaul radio based upon detecting information or receiving information informing of detected interference; and providing user payload information intercommunication with at least a second backhaul radio based at least in-part upon the operating parameters of the one or more other backhaul radios.
2. The method of claim 1, wherein the progressive interference procedure comprises: transmitting a first signature with progressively increasing interference potential for a period of time.
3. The method of claim 2, wherein the progressively increasing interference comprises one or more of: transmission at a power level with an increasing duty cycle over successive periods of time, and transmission at several increasing power levels over successive periods of time.
4. The method of claim 1, further comprising: scanning one or more radio frequency channels for the presence of said signature radio signals transmitted from the one or more other backhaul radios to generate scan data, and wherein the at least one adjustable network parameter is adjustable based on the scan data.
5. The method of claim 4, wherein said scanned one or more radio frequency channels are selected based upon said signature radio signals.
6. The method of claim 4 further comprising generating a scan report based on the scan data.
7. The method of claim 1, further adjusting the at least one network parameter is to reduce a potential of interference of the first backhaul radio with the one or more other backhaul radios.
8. The method of claim 7, wherein the adjusting the at least one network parameter comprises one or more of: selecting a frequency channel utilized between the first backhaul radio and at least the second backhaul radio for use during the second operational mode; adjusting the effective radiation pattern of the first backhaul radio; selecting one or more of the plurality of directive gain antenna elements; and adjusting the physical configuration or arrangement of the one or more of the plurality of directive gain antenna elements.
9. The method of claim 8, wherein the adjusting the effective radiation pattern comprises one or more of: steering the effective radiation pattern in elevation; and steering the effective radiation pattern in azimuth.
10. The method of claim 8, wherein the adjusting the effective radiation pattern comprises: calculating digital beam former weights based upon at least one constraint related to the potential of interference; and applying the digital beam former weights.
11. The method of claim 10, wherein the constraint is selected from the group consisting of: properties related to or derived from a scan result; a direction in which signal transmission is to be limited; parameters which reduce the potential for interfering with one or more of said other backhaul radios; parameters which increase the likelihood of said first and said second backhaul radios meeting performance goals with respect to an interposed wireless communication link; a restriction of use of specific transceivers or specific antennas of a plurality of transceivers or antennas; a use of specific polarizations for transmission; attributes of a collective transmission radiation pattern associated with a plurality of transmitters; a frequency or geometric translation of beam forming weights between receiver weights and transmitter weights; a change in antennas used or selected; a change in operating frequency; and combinations thereof.
12. The method of claim 1, further comprising assessing performance after the adjusting of the at least one network parameter.
13. The method of claim 12, wherein the assessing performance comprises one or more selected from the group consisting of: performing additional scans; performing additional scans with specific search criteria; performing additional scans with limitations in frequency, azimuth, elevation, or time; performing additional scans with a modified antenna selection configuration; performing additional scans using antennas intended for transmission during normal operation for reception during the additional scanning process; performing transmission of a signal from the first backhaul radio to the second backhaul radio, receiving a signal from the second backhaul radio by the first backhaul radio.
14. The method of claim 1, further comprising aligning an antenna array of the first backhaul radio with the second backhaul radio.
15. The method of claim 14, wherein the aligning is based at least in part upon a signal transmitted from the second backhaul radio.
16. The method of claim 15, wherein the aligning is based on a GPS location and a compass direction.
17. The method of claim 1, wherein at least one of said signature radio signals transmitted from the one or more backhaul radios are transmitted as a spread spectrum signal embedded within and simultaneously with information symbols in time from at least one of the backhaul radios.
18. The method of claim 1, wherein said first backhaul radio transmits a signature radio signal as the first signature during operation with a second backhaul radio.
19. The method of claim 18, wherein the first signature is transmitted inline with information symbols in time.
20. The method of claim 18, wherein the first signature is transmitted as a spread spectrum signal embedded within and simultaneously with information symbols.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate one or more examples of embodiments and, together with the description of example embodiments, serve to explain the principles and implementations of the embodiments.
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DETAILED DESCRIPTION
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(52) The spectrum in the embodiment defined in
SB1=7126.5−7574.5 MHz (Channels 1 to 32)
SB2=7588.5−8036.5 MHz (Channels 34 to 65)
SB3=8050.5−8498.5 MHz (Channels 67-98)
(53) Additionally Channels 33 (4B-20) and 66 (4B-40) are defined as Common Control Channels (CCC), to be used for advertising the presence of ABS devices, intercommunication between ABS devices with respect to interference coordination and other control and overhead functions in specific embodiments.
(54) Channelization
(55) In one embodiment, a network-based registry 4C-60/4C-70 (of
(56) As will be discussed associated with subsequent figures, and specific embodiments, ABS services may include multiple groups of “Tiers” of devices, each tier having specific rules by which they must operate and result in interference protection between and among tiers of devices (such devices being referred to as tiered service radios). Such rules may also provide for a fairness to access of channels to prevent some devices from unfairly using more spectrum channels than would be fair to other devices, and preventing a reasonable number of devices within a geographic region to operate simultaneously.
(57) For example, in one embodiment associated with
(58) Any given link must use and register up to 2.sup.N.sup.
(59) The selection of the number of channels for operation, as mentioned for some embodiments, may be determined based upon the tier of service a device belongs to, and determined according to parameters provided by accessing a registry and may be specific to a geographic region.
(60) In one example, for Tier 2 products, N.sub.MAX=3 (e.g. 2.sup.N.sup.
(61) In the current embodiment, the M.sub.TOT channels can be occupied by either or both transmitters at any time for a given link, and may be dependent on the Tier of service, and geographic region. An example of a geographic region is shown in
(62) Continuing with the current exemplary embodiment, M.sub.ACTUAL is the actual number of channels (up to M.sub.TOT), in use at any time. Once a tiered service radio (or tiered device) is registered, (thus, becoming a registered radio) to transmit M.sub.REG channels in any of SB1, SB2, or SB3, such a product can transmit subject to sharing rules herein, on 1 to M.sub.REG channels contiguously as available. In the current embodiment, non-contiguous Tx channels at a single transmitter are not allowed.
(63) According to the rules of the current embodiment, all transmitters (tiered service radios for example) are fixed and registered prior to first usage (including Tier 3 devices). In an exemplary embodiment, no devices are mobile.
(64) In one embodiment, the registration may include Tx location, antenna parameters, Tx channels(s) (or channel numbers), Tx power (or max tx power), signature parameters (such as code sequences, demodulation parameters, structures, identifiable aspects of the signature radio signals, etc.), acceptable co-channel sharing signatures (or classes of signatures), Tx signaling method(s), signature approach (inline versus embedded), signature power in dB relative to nominal Tx power level, and/or maximum registered Tx power. More detail and specific examples of exemplary registry entries are discussed associated with
(65)
(66) Returning to the current description, the only protection a legacy Tier 1 device 4C-10 would have is the registry 4C-70 with a pre-defined exclusion zone associated with a geographic location. Such an exclusion zone within may be defined by one or more center points, and a radius from each center point, or another definable geographic shape such as a rectangle, or an ellipse, or the like. An example of such an exclusion zone is provided in
(67) Referring back to
(68) Exemplary rules that may be required for Tier 2 devices include: Tier 2 users must not use, or must vacate upon detection, channels occupied by Tier 1 users. Tier 2 users must occasionally re-check the registry database (based upon time, duration, or the like). Tier 2 devices must advertise their presence by transmitting an Alert signal including a T2 Alert Signature, and registering within the registry data base 4C-70 (or becoming a registered radio), including the start time of their active operation and other details, such as for example, described associated with
(69) An example of a T2 device being prevented from operating, as according to the foregoing rules, is provided associated with
(70) An example of rules for an embodiment for T2 devices to achieve interference protection from other T2 users is: Tier 2 users must not use channels already occupied by other Tier 2 users as either: i. Detectable at a threshold with a valid Tier 2 signature, or ii. Registered (as a registered radio) in a look up for a geographic location within a Tier 2′s exclusion zone, unless iii. Existing channel occupant Tier 2 user with “precedence” agrees to accept the presence of the new channel occupant tier 2 user. For these purposes precedence is defined as the device having initiated continuous operation on a channel (s) earlier in time, as entered within the registry.
(71) Just as Tier 1 devices, in the current embodiment, have priority and are protected from interference from Tier 2 devices, Tier 2 devices have priority and are protected from interference from Tier 3 devices 4C-40, of
(72) Tier 3—Unlicensed Users Allowed to use up to “unlicensed max” number of channels for a specific geographic region as determined by registry look up, and Wherein Tier 3 users must not use, or must vacate upon detection of any Tier 1 or Tier 2 user at any time Wherein Tier 3 users must certify: i. Detection capability for Tier 1 and Tier 2 signatures, and ii. The ability to access the registry prior to transmitting on the ABS channels
(73) The various tiers of devices have interference priorities and obey sharing rules. However, specific embodiments may provide for certain channels to be reserved for specific tiers of operation to ensure fair access to the spectrum resources. For example, in one embodiment associated with
(74) As described above, in embodiments of ABS services, T1-Incumbent, T2, and T3 devices are required to transmit an alert having a signature sequence. In other embodiments, only T3 devices, or both T3 and T2 devices are required to transmit an alert signature. The alert signature may vary in different embodiments of the invention, and may be transmitted on the common control channels in some cases, or within the band of operation (in-band) in other embodiments. Further, when the alerts are transmitted in-band they may be “in-line” or “embedded”. One example of an embedded signature sequence was disclosed associated with co-pending application U.S. Ser. No. 13/763,530, the entirety of which is incorporated herein by reference. The structure of the alert signals and the signatures within them are described in further detail with respect to
(75) In one embodiment, all transmitters required to transmit an alert must transmit signatures having at least 0.01% (or −40 dBc) of the nominal transmit energy in every 1 s period (P.sub.NOM×1 s) based upon relative transmit time and relative transmit power.
(76) In one exemplary embodiment, a signature of duration 100 μs can be transmitted either in-band/in-line, in-band/embedded, or on the common control channel. Further embodiments may include transmitting an alert signature from a receiver antenna, so as to enhance the potential for determining interference potential and accuracy or to aid the estimation of the interference potential from other ABS devices. Such an approach may be applicable for ZDD and/or TDD based devices, or FDD devices any of which may utilize interference cancelation approaches at the receiver to remove the transmitted alert. Alternatively such an approach may utilize in-line bursts of the alert signal in designated non-reception time periods at the receive antenna.
(77) In one example of inline signaling for an in-band/inline alert, a burst signature at P_NOM transmission power level for 100 μs is utilized, one every second. In another example, an alert signature may be transmitted multiple times per second, but at a power level of
(78)
so as to result in the same integrated power over the 1-second period. As a result, a receiving device can be sure of the integrated receive power per unit time, relative to the nominal transmission power of the signal carrying information. Such a process of interference estimation further enhances the ability of the detecting device to assess the potential for interfering with the detected device upon beginning transmissions from the detecting device.
(79) In another embodiment where the alert is transmitted on the Common Control Channel (4B-20 and/or 4B-40) one alert will be transmitted at a random time within every 1 ms time period, including a 100 μs burst signature at P.sub.NOM, again allowing for the estimation of the power level of the detected alert relative to the information signal from that transmitting device.
(80) The common control channel is further available for non-protection signaling broadcasts instead of inline signatures. For example, the common control channel may be utilized for intercommunication between tiered service radios, in contrast to simply advertising the presence of the device so as to make tiered service radios of a relative lower tier refrain from interfering with the instant tiered service radio (e.g. protection signaling).
(81) One embodiment of the common control channel is available for limited frame exchanges for any Tier 2 or 3 transmitters without current registration subject to such exemplary restrictions as: P.sub.LIMIT=P.sub.NOM, and modulation is only within channel Max 100 us frame duration that is randomly chosen Max 1 frame per TX Period of 1 ms Max 100 frames per TX per second At least one signature frame per Tx per second
(82) One embodiment of a signature and associated payload will now be discussed, which includes a unique 32 bit address assigned as a 16 bit manufacturer code and a 16 bit random address. The alert may also include the transmission or reception channels, and may be modulated utilizing non-coherent DQPSK or DBPSK using a code sequence. In various embodiments, the code sequence is a direct sequence spreading code, and utilize one or more of a Barker, PN, maximal length code, CAZAC, Gold, Zadoff-Chu, and the like.
(83) In one example having 1 signature of length 100 us in a 14 MHz channel results in ≈12.39 Msym/s or 1238+ symbols/100 us when using a root raised cosign filter of 1.13. The information bits may further utilize a½ rate Reed Muller or Reed Solomon Code (for Parity Check), and be modulated according to DQPSK. One embodiment would then result in at least 37 spreading “chips” per bit, with 32 bits of information.
(84) Alternative embodiments of the structure and processing of alerts and their transmission and associated layered protocols will be provided associated with subsequent figures.
(85) Transmission Power of ABS Signals
(86) Associated with the example embodiment of
(87)
Where P.sub.NOM is the nominal power level determined from the registry for the given tier of service, and the geographic operating region.
(88) Further the maximum equivalent (or effective) isotropically radiated power for a given tiered service radio is determined by
Max EIRP=P.sub.LIMIT*G.sub.TxMAX
where G.sub.TxMAX is max Tx antenna gain limit for a given geographic zone.
(89) Each ABS device must further demonstrate and be certified to perform transmit power control over P.sub.NOM−10 dB to P.sub.MAX (where P.sub.MAX≤P.sub.LIMIT).
(90) As previously described, the alerts may be utilized so as to determine the potential for interfering with other devices within the area such that antenna and transmission parameters (as adjustable network parameters) may be adjusted so as to reduce the potential for interfering with higher tier devices, or devices of the same tier but with a earlier occupancy of the channel (precedence). As will be discussed further, upon the detection of an alert from a device of the same or lower tier, but with lower precedence if from the same tier, procedures are disclosed by which the two devices may cooperatively reduce the interference levels to acceptable levels, or by which the lower tier or lower precedent device may be forced to discontinue transmission all together. Such cooperative interference mitigation approach will be discussed associated with subsequent figures, in particular
(91) Turning now to
(92)
(93)
(94) As discussed in additional detail in this disclosure and the co-pending applications previously incorporated by reference, the use of multi-element antenna systems, in some configurations, allows an antenna array's beams, side lobes, and nulls to be advantageously directed. By the advantageous angular placement of an antenna array's main gain lobe, and the placement of lower gain portions of the antenna array's gain pattern in specific other directions, a desired link may be maintained while managing the level of undesired signal transmitted to or received from other transceiving radios (including T1-Is) in the area. The antenna arrays may utilize adaptive techniques incorporating transmission null steering or reception null steering approaches. In one embodiment, adaptive antenna array processing, including null steering algorithms, are utilized to allow for the deployment of RE-IBR 4E-20 and AE-IBR 4E-10 of
(95) In one embodiment, the antenna elements 352A of
(96) In one embodiment, the RE-IBR 4E-20 and AE-IBR 4E-10 utilize a multi-element antenna array such as depicted in
(97) Embodiments of the invention are advantageous because the impact to the T1-I link performance can be reduced or eliminated completely while allowing for the deployment of the IBR 4E-10 and IBR 4E-20 in the same geographical region as the T1-I devices 132a and 132b with sufficient inter-IBR link 4E-50 performance. In some embodiments, IBR deployments may be enabled in the same geographical areas and within the same frequency bands, and in further embodiments such deployments may be in a co-channel configuration amongst a T1-I link and an IBR link, while allowing for sufficient performance between IBR 4E-10 and IBR 4E-20.
(98) With reference to
(99)
(100) Intelligent backhaul radios RE-IBR 4F-20 and AE-IBR 4F-25 are deployed with configurations as previously discussed in the related embodiments of IBRs 4E-10 and 4E-20. The IBRs 4F-20 and 4F-25 are deployed for cellular base station backhaul with obstructed LOS propagation link 4F-60 according to one embodiment of the invention.
(101) In
(102) In the embodiment shown in
(103) As explained above, in
(104) Embodiments of the invention relate to determination of IBR network parameters (including adjustable network parameters) and the installation and commissioning process of remote end IBRs (RE-IBRs) and Aggregation End IBRs (AE-IBRs). A detailed process for installing and commissioning the IBRs (or tiered service radios in general) is described in further detail below. These processes and/or some of the process steps may be may be performed using one more of IBRs and IBCs (or Intelligent Backhaul Controller) of
(105) During installation or during deployment and operation of the IBRs 4F-20, 4F-25, the IBS, IBMS and other public and private network elements such as the registry server 4C-60 and database 4C-70 (which may collectively include a registry in some embodiments) may use information stored with one or more network elements to determine or aid in the determination of IBR operational parameters (adjustable network parameters for example) for allowing co-band or co-channel operation with manageable interference impact to and from T1-Is 4F-05 and 4F-10 or other aforementioned services within a geographic zone, or within a known radio frequency propagation distance.
(106) Exemplary IBR operational parameters (adjustable network parameters) include but are not limited to: the selection operational frequencies; the modification of transmitter antenna patterns; the modifying or selection of antenna polarization or spatial patterns; the selection of specific antennas from a set of available antennas; the selection of transmission nulls, reducing the interference impinging upon other systems; the selection of receiving or transmission digital beam forming weights, or algorithmic beam forming constraints; the physical movement, placement, alignment, or augmentation of one or more antenna elements or antenna arrays by electrical, or electromechanical control or by a request for manual adjustment or augmentation during or after installation; the modification of transmission power; and the selection of interference margin values for the reduction of the risk in interfering existing systems.
(107) In one embodiment, the determination of the IBR operational parameters (adjustable network parameters) is performed utilizing an algorithm based at least in part on the location of the T1-Is 4F-05 and 4F-10 and their radiation parameters. This information may be stored in the Universal Licensing System (ULS) operated by the Federal Communications Commission (FCC), or on other public or private databases or the registry server as shown in
(108) Further embodiments may include an iterative method. For example, the IBRs may report received spectral measurements and configuration parameters to the IBMS, which performs selection of some or all for the operation parameters, and passing the parameters to respective IBRs. The IBRs may then perform additional or refined scanning upon initial operation prior to the determination of subsequent IBR operational parameters.
(109) Upon initiating the configuration process in this embodiment, the respective IBRs perform a scan of receive channels to detect existing T1-Is. The scan process, in some embodiments, produces scan data. The IBRs then report their respective antenna configurations and scan results (scan data) to the IBMS. Note that in other embodiments, a centralized server may not be used at all, allowing for a distributed decision process based upon rules. Returning to the current embodiment, the IBMS, will determine, assuming another channel may not be used, the level of interference the T1-I will receive. In some embodiments, this determination is based also upon received signatures levels (signature radio signal levels for example) or alert level per the disclosed invention. The interference may be determined utilizing IBR effective antenna pattern adjustments and, optionally, associated information retrieved from a database of T1-I parameters. In some embodiments, the effective antenna pattern adjustments may include the use of transmission beam nulling from the required one or more IBRs to further reduce the interference levels which may be received at the T1-I, while maintaining a minimum required performance between the respective IBRs. In one embodiment, an interference margin is also calculated. The interference margin is used as an additional reduction of the required interference to the target T1-I. The interference margin may be based on a fixed amount; a level of uncertainty of the predicted interference, an amount based upon the reliability or predicted accuracy of interference calculations, or based upon using or the availability of, the specific values of T1-I antenna and operating transmission parameters retrieved from a database.
(110) In some embodiments, the RE-IBRs and AE-IBRs may operate on channels for which no interference is detected, but are within a predetermined distance of T1-Is. The distance is determined based on the geographic location of the IBRs and the T1-Is. The location of the T1-Is may be determined by accessing, for example, the FCC (ULS) database. In such situations, the IBMS may utilize an interference margin value or other operational constraint value based upon propagation models to further reduce the likelihood of interfering with the T1-I.
(111) In some embodiments, co-existence of the IBRs with FDD T1-Is may be required. In these embodiments, interference margins or operational transmission constraints, including transmission beam nulling, may need to be calculated. For example, in one embodiment, the selection of the transmission antennas to utilize for receive during a scan procedure during configuration may allow for enhancement of transmit beam forming and transmit nulling operations and may further aid in the determination of values related to transmission beam nulling.
(112) In some embodiments, received signals transmitted from a T1-I 4F-05 operating in FDD are detected during a scan procedure at an IBR 4F-20. However, the IBR to IBR link, in one deployment, is configured to operate on the specific FDD paired frequency co-channel used for receiving by the FDD T1-I 4F-05 as determined, for example, by the IBMS 420 in
(113) Embodiments of the invention allow for IBR adjustable network parameters to be selected to avoid co-channel operation with T1-Is. In deployments where co-channel operation between the IBRs and T1-Is is not avoidable, the impact on link performance to the T1-I 4F-10 and from T1-I 4F-05 can be reduced or eliminated completely while allowing for the deployment of the IBR 4F-20 and IBR 4F-25 in the same geographical region with sufficient inter-IBR link 4F-60 performance. In some embodiments, the IBRs may be deployed in the same geographical areas and within the same frequency bands as T1-Is. In some embodiments, the IBRs and T1-Is may be deployed in a co-channel configuration, while still allowing for sufficient performance between IBR 4F-20 and IBR 4F-25.
(114) Referring now to
(115) Embodiments of IBR MAC 512A generally incorporate the functionality of the various embodiments of IBR MAC 312A. Some Embodiments of IBR MAC 512A may additionally include MAC processing supporting the optimization of the wireless links utilizing ECHO devices as described more fully in co-pending application U.S. Ser. No. 13/763,530, the entirety of which is incorporated herein by reference. Additionally some embodiments of IBR MAC 512A will support peer to peer and communications with other devices (e.g. ECHO devices) utilizing a Signature control channel for the transfer of control information.
(116) Embodiments of the Signature Link Processor (SLP) 500 provide for the reception and insertion of an additional wireless communications channel referred to as a Signature control channel in specific embodiments. Associated with IBR transmission, the Signature Link Processor receives transmit symbol streams (1 . . . K) from IBR Modem 324A and provides the same transmit symbol streams (1 . . . K) to the IBR Channel MUX 328A with additional Signature control channels added to the individual streams, if such processing is enabled. In some embodiments where Signature control channels are not actively associated with any specific transmit symbol stream, the transmit symbol streams are passed to their respective with no addition of Signature control channel signal. Embodiments of the SLP may provide for a unique Signature control channel to be added to each of the respective transmit symbol streams. In other embodiments the SLP may provide for the components of the control channel or the control channel in entirety to be added commonly to all transmit symbol stream in a related fashion.
(117) In one exemplary embodiment utilizing a common control channel structure, a direct sequence spread spectrum (DSSS) pilot signal utilizing a first orthogonal code will be added commonly to all streams processed for transmission by the SLP. Additionally, in the instant embodiment, each individual stream will receive a respective second copy of the DSSS pilot signal, but modulated with a differing orthogonal code respectively associated with the individual transmit symbol streams. Such modulation may be accomplished using modulo 2 additions, multipliers, or bi-phase modulators as known in the art. The individual orthogonal codes may additionally be modulated by information bits in the form of the IBR_SLP_Data transmit data interface stream, resulting in a Signature control sub-channel symbol stream. One such reference teaching DSSS and CDMA modulation and demodulation techniques is CDMA: Principles of Spread Spectrum Communications, by Andrew J. Viterbi (Addison Wesley Longman, Inc., ISBN: 0-201-63374-1). Some embodiments of the Signature control channel having a specific structure utilizing multiple sub-channels are referred to as a common control channel. The use of either term in specific instances should not be considered limiting, and in some cases is utilized interchangeably.
(118) Embodiments of the Signature Link Processor (SLP) 500 further provide for the reception and demodulation of Signature control channels inserted into one or more transmitted symbol streams by other devices, such as an ECHO device. Associated with IBR reception, the Signature Link Processor 500 receives receive symbol streams (1 . . . L) from IBR Channel MUX 328A and provides the same transmit symbol streams (1 . . . L) to the IBR Modem 324A, with the detection and or demodulation of any associated Signature control channels within the individual streams, if such processing is enabled. The resulting demodulated data from the Signature control channels is provided to the IBR MAC 512A by the SLP 500 as IBR_SLP_Data. Embodiments of the SLP may provide for a unique Signature control channel to be received and demodulated associated with each of the respective receive symbol streams. In other embodiments the SLP may provide for the components of the control channel or the control channel in entirety be detected and demodulated commonly from all receive symbol streams.
(119) In alternative embodiments, with appropriate interfaces, the SLP may be placed between the IBR Channel Mux 328A and the IBR RF 332A so as to allow for a single Signature control channel on a per transmit or receive chain basis rather than on per symbol stream basis.
(120) In yet further alternative embodiments, a similar per chain Signature control channel result may be obtained utilizing the SLP placement as shown in
(121)
(122) Additionally, the DRx-kl signals (where kl varies from 1 to KL) provide for digitally sampled signals associated with the 1 to L receive symbol streams, in some embodiments. The DRx_Out-kl signals (where kl varies from 1 to KL) are respectively coupled to DRx-kl, to provide for a pass through operation of the respective DRx-kl signals, for example when an SLP is utilized within an IBR. Such a pass through coupling, in some embodiments, allows for the coupling of the receive symbol streams from the IBR Channel MUX 238A to the IBR Modem 324A. In some alternative embodiments where the SLP is utilized within a repeater device, such DRx_Out-kl signals may not be utilized by the repeater device and may not be depicted as external ports to the SLP in such embodiments.
(123) The DTx_In-kl and DTx_Out-kl signals (where kl varies from 1 to KL) provide for a digitally sampled signals associated with the 1 to K transmit symbol streams respectively input and output from SLP 500, in some embodiments. An individual Signature Control Channel Modem 510B-kl, provides a modulated control channel (MTx-kl) to a respective exemplary Adder 514B-kl, which combines MTx-kl with the input transmit symbol stream DTx_In-kl. Adder 514B-kl in turn provides the Signature Control Channel Signal DTx_Out-kl. In embodiments where no input to a particular DTx_In-kl is provided, the MTx-kl signal is provided directly as DTx_Out-kl.
(124) Note that KL need not be equal to either K or L. In some embodiments where there is a one to one correspondence between transmit symbol streams and Signature control channels (or sub-channels in a common control channel structure), KL must be equal to or greater than K. In cases where KL (the number of SCCMs) exceeds K (the number of transmit symbol streams) the excess SCCMs may not be utilized for transmission, or may be used for other purposes. One such purpose would be for use dedicated to a transmit chain, such as might be used with a single high gain antenna panel for example.
(125) Further, when there is a one to one correspondence between the number of receive symbol streams and the number of Signature control channels associated with these streams, KL (number of SCCMs) must be equal to or exceed L (number of receive symbol streams). In the case where KL exceeds L, a number of the SCCMs may remain unused for reception of Signature control channels, or may be utilized for other purposes such as receiving Signature control channels from individual receive chains.
(126)
(127) As mentioned previously, such DSSS and CDMA transmission and reception approaches and structures are well known in the art including as utilized in the downlink of IS-95, W-CDMA, CDMA-2000 and the like. Further aspects of such art is disclosed in the previously references book CDMA: Principles of Spread Spectrum Communications, by Andrew J. Viterbi (Addison Wesley Longman, Inc., ISBN: 0-201-63374-1).
(128) An alternative embodiment, not shown, of the SLP 500 of
(129)
(130) In a related embodiment, inline signatures/alerts 5D-20,40 are sent at the maximum allowable transmission power of the transmitter. In other embodiments, the alerts (inline signatures 5D-20,40) are transmitted at the same average transmission power level as the composite ABS information signal (5D-10,30,50) it is inline with, during the inline transmission period. Other embodiments may provide for the alert transmission power to be set at a ratio relative to the user information signals (5D-10,30,50), or the like.
(131) For some embodiments using inline, in-band communications, timing constraints related to the transmission of the alert signals are required, but may allow flexibility within a pre-defined window. In one embodiment, it is undesirable to require a fixed periodicity for the inline signature. Such an arrangement may be too rigid for specific embodiments. In such an embodiment, inline transmission periods could be:
(132) i. Shorter than T.sub.Max.sup.Alert
(133) ii. Longer than T.sub.Min.sup.Alert
(134) iii. where T.sub.Max.sup.Alert=T.sub.Min.sup.Alert+T.sub.VALID.sup.Alert
(135) Referring again to
(136)
(137) BW.sub.signal represents the entire bandwidth, or equivalent number of occupied minimum channels BW.sub.CH_Min in use by a specific ABS compliant system, in one embodiment. In this embodiment, the modulation symbol rate of the user information signal 5E-10,30,50 will be proportionally faster (by the ratio of BW_Signal/BW.sub.CH_Min) than that of the alerts (5E-20A-D, 5E40A-D). This is because the individual alert signals (5E-20A-D, 5E40A-D) in this embodiment are sent in a manner consistent with those sent for an individual channel as depicted in
(138)
(139) Alternatives not utilizing orthogonal codes are possible as well, for instance using two different m-sequences for each of the I code and the Q code where the length of each m-sequence is equal to L.sup.SIG and includes the signature sequence(s). Alternative codes which may be utilized include Barker codes, gold codes, and others and known in the art.
(140) Referring now to the embodiment of row C, two sets of signature sequences 5F-30A, 5F-30B are sent per one alert time period (L.sup.SIG=1/2*L.sup.ALERT). Each signature information bit S(n), where n=0 to 3, may be utilized so as to produce a number of different modulation formats including both coherent modulations, and differentially encoded modulations. Some example modulations utilized in various embodiments include DBPSK and DQPSK using differential encoding; and BPSK, QPSK, QAM utilizing a phase reference such as a pilot bit, pilot symbol or pilot channel). Various codes and modulation structures may be utilized as described in the foregoing.
(141) Row D of
(142)
(143)
(144) In order to prevent the combination of individual alerts of different composite alert signals 5G-25 and 5G-35, a gap of time between the T.sub.VALID.sup.ALERT periods is defined so as to ensure only individual alert signals of the same composite alert signal are combined together. The spacing between successive T.sub.VALID.sup.ALERT periods are defined by T.sub.Min.sup.ALERT and T.sub.Max.sup.ALERT previously discussed, and depicted within
(145) In embodiments of an ABS system utilizing embedded signatures, the embedded alert signals will act as noise to the user payload bearing signal (5G-10,5G-30). In some embodiments, the alerts have a code length k providing a “processing gain” resulting from a correlation in a receiver of 10*log 10(k), as previously discussed. If k is sufficiently large, the alert signal(s) may be transmitted at a relative power level reduction P.sub.Emb.sup.ALERT such that the interference resulting form the embedded signal is manageable with no further processing. For example, if the modulation for the ABS payload information signal requires 25 dB of signal to noise and interference
(146)
to be demodulated with a reasonable error rate, an interference level 10 to 20 dB below this level (I.sub.Margin) would be appropriate. Note that within this discussion the term SNR may be understood to include interference as well, and the interference aspect may not be explicitly mentioned in every instance. As a result of the desired SNR for the demodulation of the ABS information payload signal, within this embodiment, the power of the alerts would be set to a value below the payload information signal by P.sub.Emb.sup.ALERT=25 dB+I.sub.Margin. This relationship assumes that the “chip rate” of the alerts, is comparable to the symbol rate (or sample rate) of the ABS information signal within the relevant channel bandwidth. In contrast to the SNR considerations for the payload information bearing ABS signal, the received alert signals must also be detected with a sufficient SNR, which is an opposing motivation. In general, for a high probability of detection of the signatures, any metric utilized to perform detection should have a signal to noise ratio allowing for an acceptably high probability of detection and an acceptably low probability of false detection. One approach to achieving a high probability of detection is to transmit the alerts signals at a higher level, thus impacting the SNR of the information-bearing signal. However, the relative transmission power of the alert signals in the current embodiment is set by P.sub.Emb.sup.ALERT=25 dB+I.sub.Margin.
(147) A discussion of the signal to noise ratios associated with the probability of detection and false detection may be found in CDMA: Principles of Spread Spectrum Communications, by Andrew J. Viterbi (Addison Wesley Longman, Inc., ISBN: 0-201-63374-1) pages 48 to 52 and elsewhere. In some embodiments, the resulting signal used to determine detection of the embedded composite alert signals will be the result of the correlation of the individual alerts, and then the combination of the individual alerts into a signal detection signal, which will be used for a detection hypothesis, against a metric. Just as the alert sequences act as noise to the demodulation and successful detection of the information symbols of the ABS information signal, the information signal will act as noise to the successful detection and demodulation of alert signals. Therefore, the processing gain (e.g. the length of the alert signature k) must be sufficiently long, in some embodiments, so as to provide an alert detection SNR that allows for an acceptable probability of detection and a sufficiently low probability of false alarm, associated with the transmission of the alert signatures P.sub.Emb.sup.ALERT dB below the information payload signal.
(148) In one embodiment, a detection hypothesis for alert signals is based upon a ratio of the correlated to uncorrelated energy of the alert sequences. Such a test has the added benefit of reducing false detections in the presence of very strong uncorrelated signal levels in contrast to a test based upon correlated energy exceeding a threshold. An example of one such test is based upon the following hypothesis:
(149) Alert detection Det(h), if
(150)
where, Receivers must integrate for N.sub.MaxAlerts, where N.sub.MaxAlerts is equal to the maximum number of alerts which are possible within the time window T.sub.VALID.sup.ALERT, and for each h. h is the alert code sequence(s) start time under the current hypothesis being tested.
(151) The above test allows for the detection of either inline or embedded alerts with a certain probability P.sub.Detect.sup.Alert of detection, and a certain probability of false detection P.sub.False_Detect.sup.Alert. Such a process requires performing the above test over all possible start times of the alert signal within T.sub.VALID.sup.ALERT.
(152) While the forgoing discussion includes embodiments for embedded alerts, which balance the transmitted alert signal power with interference to the ABS information signal, alternative embodiments allowing for a higher transmission power of the alerts may be utilized which provide for both a higher alert transmission power, and maintaining the SNR of the ABS information payload signal at the intended receiver(s), through the use of interference cancellation at the intended receivers. Despite such an alternative, the detection hypothesis test of Eq. 5-1 may be utilized with interference cancelation at the receiver as well.
(153) Interference cancelation in this context provides for subtracting a known undesired interfering signal from a total received signal to result in a remaining signal that has an improved SNR. The use of embedded alerts is one such situation allowing for the use of interference cancelation at a receiver attempting to receive the ABS information payload signal because the signature(s) (the exact codes) of the alerts are known a priori to the reception of the signal as having been defined as part of the overall system, or communicated as part of an overhead message of some sort between the transmitter and the receiver. Further, the power level relationship and likely the phase relationship between the information signals and the alert signals may be known as well in some embodiments. In general, each “unknown parameter” such as amplitude, phase, information signal, code sequence, etc., are estimated to allow the generation of an estimated interfering signal to allow for the actual interfering signal to be cancelled utilizing a subtraction of the estimated interfering signals from the total signal where the total signal contains the actual interfering signal (or signals). The more parameters that are known before hand (such as code sequence, amplitude, phase, and timing) the fewer parameters require estimation, thus reducing the complexity and opportunity for error in an implementation at a receiver. Such processing (an interference canceller) may be implemented in some embodiments after down conversation, digitization, and spatial processing, but prior to demodulation of an individual stream. For example referring back to
(154) Embodiments of structures for receiving and transmitting alert signatures, and signals were, in part, described associated with
(155) In some embodiments where a device must be able to detect both an inline and an embedded signature signal using a single receiver structure, it is contemplated that the chip rates of the inline and the embedded are to be the same, and only the power level versus repetition number be different. In related embodiments, the detected alert power ideally would result in the same or a substantially similar level, independent of the alerts being embedded or inline. Such embodiments may allow for determining information relating to the received level of the ABS information payload signal based upon the detected alert signal level. Such information, in specific embodiments allow for an assessment of the potential for interference with or from the transmitting ABS station as discussed previously.
(156)
(157)
(158)
(159) Sliding Detector 5J-10 includes CSCB 5I-10. The sequence set (SSj) is provided by the Sliding Detector Control input, which provides additional control inputs in various embodiments. The Mag and Mag{circumflex over ( )}2 outputs of 5I-10 are provided, in one embodiment, as outputs of Sliding Detector (SD) 5J-10, and as outputs of the CSCB 5I-10. Other embodiments of a Sliding Detector 5J-10 and/or CSCB 5I-10 may have only one or neither of such outputs, potentially depending upon the embodiment of detector/demodulator, such as 5K-00 of
(160) Additionally, in the current embodiment, output XC_Sj_B(n) is provided to complex multiplier 5J-50. In certain embodiments, the conjugated signal from 5J-40 represents the phase (mathematically conjugated) of the received signal for a pilot CDMA channel derived from a correlation with the CSCB using one or more orthogonal codes (as described above in one embodiment), and providing for a demodulation of a pilot code channel. Further, the signal resulting from 5J-30 may represent a data CDMA channel resulting from the CSCB 5I-10 utilizing one or more other orthogonal CDMA codes, potentially including one or more “cover” PN scrambling codes (again as described in the foregoing on one or more embodiments). In such an embodiment, using a CDMA pilot code channel and CDMA data code channel, the de-spread and de-multiplexed information symbol SMj(n) is provided as an output of the Sliding Detector 5J-10.
(161) In another embodiment, where a coherent pilot signal is provided to the in-phase portion of the transmit signal (as S(0) of
(162)
(163) In one embodiment, the slicing of the detected modulation symbol is not performed within 5K-30 but performed in a subsequent block, such as Detector Controller 5K-40 or elsewhere in the IBR.
(164) Coherent demodulation has been described in forgoing embodiments, but in various embodiments, Detector Controller 5K-40 and/or Detection Logic 5K-30 may perform differential demodulation as well, such as DQPSK, DBPSK. For example, the Detection Logic 5K-30 may store symbols for differential processing. In yet additional embodiments, a single code may be used rather than two in some embodiments of differential modulations.
(165)
(166) The timing of the addressing may be determined and may be adjusted by monitoring detections performed by the Detection Logic 5L-30 in combination with Detection Controller 5L-40, thereby allowing for the synchronization and tracking of the T.sub.VALID.sup.ALERT periods and the appropriate aligning of the associated times so as to allow for coherent integration. Further, an intermediate threshold, in some embodiments, may be performed so as to allow for a determination of the current number of alert signature repetitions to include within the coherent integration, thereby individually detecting each repetition, or a subset of repetitions. Some embodiments may include a more robust information field allowing for the explicit signaling of the number of repeated signatures to be determined form the signal itself. In at least one embodiment, the number of repetitions is known a priori, and in yet other embodiments, the number of repetitions and other information related to the modulation format or timing of transmission is determined from the central registry (4C-60 and/or 4C-70 of
(167)
(168) The Control Plane is responsible for ABS relegated operation involving the procedures and associated messaging required to be compliant with the ABS Rules as previously discussed, and will be discussed in specific examples associated with subsequent figures.
(169) ABS-ME (management entity) is the highest portion of the ABS Control Plane, and is responsible for topology management, processes management, configuration, and interfacing to other ABS peers. The ABS ME interfaces to various “host” radio entities (IBR/IMBS entities in some embodiments), including interfaces to IBR-RLC, IBR-RLP, and even IBR-MAC for timing in some embodiments.
(170) The ABS ME further interfaces to other ABS stack entities as well to perform required functions in some embodiments. In some embodiments the ABS ME interfaces to other layers directly, while in other embodiments associated sub-layers are called upon to interface to the required ABS stack sub-layer. For example the ABS-ME configures/controls MAC to scan for interference, in one embodiment directly, and in other embodiments utilizing the ABS RRC. In the non-limiting subsequent example discussion, it will be assumed that each layer interfaces with the layers directly above or below the layer under discussion. It should be noted that other embodiments may interface in various other ways, including directly between non adjacent layers.
(171) Returning now to the discussion of the ABS ME, example functions performed include: configures/controls MAC to broadcast signature, interfaces to IBR IBMS Agent, interfaces to ABS-RRC to send standardized messages to other ABS-RRC entities, requests ABS specific procedures from the ABS-RRC, such as so-called -“progressive interference” or “blooming”. These procedures will be discussed in more detail associated with subsequent figures.
(172) The ABS Radio Resource Control (RRC) interfaces with the ABS-ME and the ABS PDCP to perform services including control/peer messaging, state management, ABS message composition, and interfaces with other ABS-RRCs.
(173) The ABS Packet Data Control Protocol (PDCP) interfaces with the ABS RRC to: arbitrate user plane and control plane priority for access to the ABS-RLC, perform “RLC “Framing” by adding a ABS-RLC header, “whitens the payload” (no 6 sequential is in a row for example), and Ciphering (encryption). The ABS-PDCP Message header addition includes a synchronization field (for example “111111”) and a logical channel index of 2 bits. The logical channel indication includes (as one example embodiment):
(174) 00—EOP (End of Packet)
(175) 01—ABS RRC (Control Plane)
(176) 10—ABS UP (User Plane)
(177) 11—reserved
(178) The ABS Radio Link Protocol (ABS-RLP) interfaces to the ABS-PDCP and the ABS-MAC to provide services to the ABS_PDCP and higher layers. Functions performed by the ABS-RLP include:
(179) Fragmentation into N bit PDUs, where in one embodiment N=1 for inband and N>1 for out-of-band fragmentation. Other embodiments may provide for inband signaling utilizing N>1 through the use of higher order modulation, and/or multiple alert sequences such as embodiments as described associated with
(180) Forward error correction (FEC)
(181) Cyclic Redundancy Check (CRC)
(182) The ABS Media Access Control (ABS-MAC) interfaces with the ABS-RLP and ABS-PHY layers to provide services to the higher layers. The ABS MAC, in specific embodiments, performs the following example functions:
(183) Transmission/reception timing
(184) Out of band access to the media (listen before talk for out of band)
(185) In-band signaling access to the media
(186) The ABS physical layer (ABS-PHY) interfaces with the ABS MAC to perform (in one embodiment) the following example functions:
(187) Transmission/reception
(188) Modulation/Demodulation using
(189) Interfacing with one or more of channels/formats:
(190) Out of band: Common Control Channel
(191) In-band inline,
(192) In-band embedded
(193)
(194)
(195) Once the first detection has occurred, the timing variables are set in Initialize step 6C-20. In some embodiments, one or more of the variables may be set during initial system configuration as well. In the current embodiment, these variables include in the current embodiment, T.sub.Max.sup.Alert, T.sub.Actual.sup.Alert, T.sub.Min.sup.Alert. Next, the MAC link processor waits for T.sub.Min.sup.Alert, in Step 6C-30, and then begins waiting for the next PHY indication of a subsequent valid detection in Step 6C-40. If no symbol is detected within T.sub.VALID.sup.Alert(step 6C-50) then processing proceeds to step 6C-70 where the higher layer RLP is notified and reset. Such an occurrence may happen is signal is lost, of if the end of the current RLP frame is received. Alternatively, if an alert is detected for the specified peer MAC (as determined in the current embodiment by a property of the alert code set (SSj) such as a secondary orthogonal code for example), the appropriate timer values are adjusted and processing returns to step 6C-30 (the wait for T.sub.Min.sup.Alert step). In the current embodiment, various alerts may be received, and for each alert signature which is distinguishable from those from other ABS-MACs, a separate ABS-MAC receive process may be instantiated, along with individual timer values.
(196)
(197) Processing then proceeds to step 6D-60 wherein the MAC waits for an indication from the RRC (in control of the fine scale timing in the current embodiment) to indicate authorization to transmit, if such authorization is required (associated with specific embodiments). Next, decision step 6D-60 directs processing based upon T.sub.VALID.sup.ALERT being valid. If expiration has occurred, an indication to the RLP is performed wherein a failure is signaled in step 6D-80. Alternatively if T.sub.VALID.sup.ALERT remains valid, processing proceeds to step 6D-90 wherein the MAC PDU is transmitted. The format of the MAC PDU in some embodiments is a simple pass through to the PHY. In other embodiments a MAC header, or other information may be added to the MAC SDU prior to the MAC PDU being provided to the PHY. Finally, successful transmission is indicated to the RLP, and the process is exited in step 6D-100.
(198)
(199) The RLP then next adds the Sync field 6E-10, the CRC field 6E-40, and performs FEC processing adding tail bits 6E-80. The result is passed to the MAC as a RLP PDU/MAC SDU.
(200)
(201)
(202)
(203) Embodiments of the Bloom process include incrementally “progressive interference”, so as to initially have a lower impact in terms of interference to any existing ABS devices which happen to be with the propagation range of a new ABS device being brought up for operation. For example, a Tier 2 device being brought up in the vicinity of a Tier 1 Incumbent device with settings in the registry allowing for other devices to operate in the region but with limitations so as to not interfere with the T1-I device require, in one embodiment, a Bloom process. In fact, in some embodiments, any device having a lower tier, or same tier and having a lower priority or right to operate in the vicinity of other devices either as reported by a registry, or detected directly in some cases use a Bloom process. Such a process allows for the higher tier, or priority device (one having been operating in the area longer but of the same tier) an opportunity to detect interfering transmissions from a device performing a Bloom process. Such a process allows the level of interference to be detectable, but not necessarily catastrophic to the link of the existing devices. Step 7C-20 provides for the RRC to configure the Bloom process, defining in one embodiment a variable “Step” with a value of 0, initially. Additionally the other layers of the ABS stack are configured as well. Next, in step 7C-30, the RRC initiates the ABS Bloom process utilizing parameters TXPower(n), and DutyCycle(n), where n is the step in the progressive Bloom process. After each step in the process, as the process returns to step 7C-30, the setting will be retained for a period of time referred to as Dwell. The process stays in 7C-40 until the Dwell process for Step n has expired. In one embodiment, the transmit power will be the full Tx power expected for operation of the link, and the duty cycle as determined by DutyCycle(n) for each step n of the Bloom process, will be varied in increasing percentages of a pre-determined repetition time for the Dwell time, which may be varies as well on a per Bloom step process. In other embodiments, both the transmission power and the duty cycle will be varied progressively. In yet further embodiments, only the power will be varied, for a given duty cycle, or in any linear, or non-linear combination. In one embodiment of the Bloom process, only the basic alert signature is sent with no identifying information. In another embodiment, the alert signature is sent with a code unique, or another property unique to station in the Bloom process. In yet further embodiments, the Bloom process includes the identity of the transmitting station in the transmissions, and potentially additional information.
(204) During the dwell process, prior to the expiration of the Dwell timer, or counter, the ABS station monitors communications channels (in various embodiments one or more of the common control channel, the inband control channel, or another out of band link) in step 7C-40 for any “direct messages” from another station notifying the Blooming ABS station of detected interference. Additionally, in step 7C-50 the Blooming ABS station checks the registry periodically for notification of detected interference due to the Bloom process. If either step receives an indication of detected interference, the process proceeds to step 7C-80 and the process (and the transmissions) are terminated in one embodiment. Note that in some embodiments, the process may be begun again, with adjusted transmission parameters so as to minimize interference to the station that detected the Bloom interference. In some embodiments, the indication of interference from another ABS station will include information usable to aid the Blooming station to avoid interfering with the detecting station with higher priority (either higher tier, or more seniority for example). Examples of the type of information usable to set interfere avoiding transmission settings were discussed previously in this disclosure associated with
(205) Returning now to step 7C-40, once the Dwell time has expired, and no interference indication has been detected, the Bloom process Step is incremented in 7C-60, and processing proceeds to step 7C-70. If the Step is the Final Step, the process is terminated in 7C-80, otherwise the process continues with new transmission settings in step 7C-30.
(206) Further details of the “bring up” of an ABS station, and the associated management of the Bloom process will be discussed associated with
(207)
(208) The table includes example registry entries for several different tiers of stations operating under the proposed ABS rules. The first column defines possible entries for one aspect of one embodiment of the registry. The FCC ID is typical of devices registered with the FCC, and is also required as noted with the white spaces rules.
(209) The MAC Address is a 48-bit IEEE assigned address which can be used to identify a station from transmissions in one embodiment.
(210) Lat, and Long provide the geographic latitude and longitude of the location of the ABS transmitter station.
(211) In addition to Lat/Long, the Address may be entered as well and may be mandatory for a fixed station in some embodiments.
(212) The Tier entry defines the class of service the ABS station is operating under as define in forgoing sections.
(213) Tx Power defines the transmitter power of the ABS station. In some embodiments, it is the maximum allowable transmit power, while other embodiments include the actual transmitter power, or transmitter power the station is capable of transmitting.
(214) Antenna Type indicates the type of antenna. For Tier 1 devices, this is more likely a fixed dish type antenna similar to entries for FCC Part 101 licenses. The Azimuth (Deg) and Elevation (m) relate to the antenna directivity and center pointing direction of a fixed antenna. Further examples include, but are not limited to azimuth beamwidth, elevation beamwidth (in degrees, not m), polarization, antenna height, azimuthal and elevation bearings at center of the pattern, etc. For devices of other tiers, or potentially for Tier 1 incumbent devices is some cases, the antenna type may further include whether the antenna is an antenna array, and any associated array attributes such as the array geometry (number of elements, and their relative geometric position), the number of receiver and/or transmitter elements, array capabilities such as receiver and transmitter null steering capacities, and the like.
(215) Equipment ID is the FCC certification ID of the equipment being used and having been certified under ABS rules.
(216) “Using Common Control Channel” is an entry for defining which common control channel, if any, a particular station is utilizing.
(217) M-ACTUAL, M-TOT, M-REG, and Registered Channels(1 . . . M-REG) as discussed previously relate to the allowable and in use channels for operation under the ABS rules.
(218) Duplexing Mode defines time division, frequency division, or so called zero division duplexing methods (or other such methods as may become applicable).
(219) Licensed C/I (dB) is an entry of an embodiment in which the fees paid, and/or the license received (Tier 2 in one embodiment) defines a C/I for which the station receives interference protection assuming it is the highest tier, and has the seniority in that location. Further detail will be provided relating to “cooperative” interference mitigation and the Bloom process associated with the ME in
(220) The SIP Address entry is an example address in some tiered service radios by which a station may be contacted with a so-called direct message. For example, in a Blooming process when notification that the Blooming station is causing interference to another protected ABS device, a directed SIP message is sent to the Blooming station in one embodiment.
(221) The P-MAX (dBm), P-NOM (dBm), P-Allow (dBm) are associated with the cooperative interference process for non-Tier 1 devices, and in one exemplary embodiment, are discussed in more detail elsewhere.
(222) The Date Occupied (or optionally also Time Occupied) and Date Licensed fields are related to determining seniority between ABS stations of the same tier. The Geographic Region field defines the specific region in which a device is operating. Geographic regions were discussed in more detail relating to
(223)
(224)
(225) Referring now to Step 8C-10 the ME of the ABS device, checks the registry for any T1 (Tier 1) or T2 (Tier 2) devices in the local proximity for which in must consider interference and previous discussed. Of course for a Tier 3 device, other T3 devices are also checked in the registry as well (see step 8D-10). In step 8C-20 the ME determines channels not in T1 exclusion zones or currently used as T2 Channels. For T3 devices, other T3 devices must be considered as well. In step 8C-30 if no unused channels are available, step 8C-40 is performed, otherwise processing proceeds to step 8C-140. In step 8C-140, when clear channels are determined to be available, the ME configures the radio entities (layers), and registers the current configuration of the ABS station with the registry. The ME then begins broadcasting alerts, and notifies (in some embodiments) the IBR IBMS, which begins transmission to peer point to point radios or point to multipoint radios for payload traffic. The ME additionally begins to monitor the Registry and/or control channels for interference messages or any direct messages.
(226) If no “clear” channels are available, step 8C-40 is performed and the ME determines from the Registry, which channels are candidates for use, so as to avoid or minimize interference to other T2 stations in the current embodiment. In step 8C-50, the ME requests ABS RRC to perform a scan of candidate channels for operation so as to assess the interference potential of using these channels. Processing then proceeds to step 8C-60, where the ME determines the best candidate channels for operation based upon scan results and registry information. Such a determination will, in some embodiments, involve propagation modeling and interference mitigation techniques as discussed. The Bloom process is then begun in step 8C-70. ME begins “Bloom Process” and monitors the Registry and in-band and out-of-band channels for direct messages. The decision as to whether direct messages are received or not is performed in step 8C-90. If no direct messages are received, the registry is checked for interference notifications in step 8C-130. If no interference notification is received, the processing proceeds to step 8C-140 as previously discussed. Returning to step 8C-90, if a direct message is received, step 8C-100 is performed where the ME will stop transmission and perform an interference mitigation process in one embodiment. Such an interference mitigation process, in some embodiments, includes responding to the “interfered with” station via direct message to negotiate cooperative interference mitigation interaction and measurements. Such mitigation may also include adjustments and “trial” test transmissions with iterative feedback from the partner “interference mitigation” station. If the interference is resolvable (8C-110) the processing proceeds to 8C-80 where the radio is configured with the determined radio parameters to avoid interference, and operation returns to 8C-90.
(227) If the interference is not resolvable in step 8C-110, processing proceeds to step 8C-120 and transmission is halted and alternative channels are selected, and the process is restarted at step 8C-60.
(228) The “Bloom process” as discussed allows for progressive interference without initially being catastrophic to the station being interfered. In one embodiment, the process is a time division process wherein less than 100% transmit duty cycle is employed. For example, the Blooming ABS station may start at 10% and proceed to 20% and so on in the current embodiment. This is less damaging, and should not “shut off” the victim station. In one embodiment, if at any point the Blooming station receives a direct message indicating unacceptable interference, then the lower tier or lower priority Blooming ABS station has to cease and desist if requested to do so. The stations performing the Bloom process must be certified, as do the stations indicating they are being interfered to allow for the transmission of messages ordering another station to vacate certain channels.
(229) In one embodiment, using the Registry, the registry control and arbitration processes between stations serves to order interfering stations to vacate certain channels. The registry time stamps registration so as to document the specific chronology of the ABS stations in a geographic area and can determine “priority” for same tier devices so as to arbitrate disputes and enforce rules. A station may send an “interference notification” message when interfered with, which is valid only if that station has been in the location earlier than the blooming stations. To ensure this process is legitimate, the Registry, as mentioned, can act as a policy arbitrator and enforcer based on the time of registration of the individual stations, or as a general process following procedural rules and steps. In some embodiments, there may be a requirement to accommodate others reasonably and work with them via the “cooperative interference mitigation process”. Such a requirement may be conditional based on the tiers of the stations, or the density of the stations within the area. For example, if one station can accommodate another station without affecting the performance of their link, they may be required to do so, or report that they cannot make adjustments. In some embodiments, the Registry may provide a benefit to that station in making accommodations for other stations in terms allowing more capability or an increase in the priority registration, for example.
(230) In one embodiment the station notifying another station of harmful interference has the obligation to inform the interfering station of the level of interference and potentially other helpful information so as to aid in the reduction of interference and to verify that the interfering station is the correct one or that the message is not fraudulent, for example. Such an indication may be considered a “hint” as to how much of a change needs to be made, or if resolution is possible at all. Such information may include the frequencies the interference is occurring on, and the level of the interference as two examples. Other embodiments may include the channel state information or angle of arrival of the interfering signal.
(231) In another embodiment, where an interfering station is being evicted from the currently Blooming or operating frequencies, the station must be given a interference mitigation time to resolve the interference in terms of adjustment of RF parameters as discussed. In one embodiment, a “notice message” or interference notification includes the specific overlapping channels, and by the specific amount of power. The mitigation may be considered a “cure time” from the first notice. Upon a second notice the station, in one embodiment, turns off transmissions immediately, unless a cooperative interference mitigation process is deemed to be ongoing.
(232) An example of such a cooperative interference mitigation process follows:
(233) 1) When an ABS station detects another is interfering, it may invoke the eviction process.
(234) 2) The “interfering” station has 1 second to “cure” and must be informed by how much the interference must be reduced.
(235) 3) If direct messaging is implemented, one set of rules apply, if a “mail box” approach using the Registry is performed a second set of rules are utilized, which are less interactive and cooperative (in the current embodiment). Such a process is designed to “align interests”.
(236) 4) If there is a direct message, and notice, but not response from the interfering station, they are required to immediately terminate transmissions (which may be based upon the registry mail box notification process).
(237) 5) If there is notice to an interfering station via a direct message, and the interfering station responds, then that station will get an opportunity to fix the interference by adjusting RF parameters. For example, if a station wants to have the opportunity to stay and attempt to adapt, it must send a response to the registry in one embodiment, or directly to the notifying station (in the current embodiment).
(238) 6) If a notified ABS station estimates that it can cure the interference problem, and makes adjustment but does not respond to the notifying station, then if such adjustment has resolved the issue, no termination occurs as the secondary notice will not occur.
(239) 7) However, if a notified station does not respond, and attempts to fix the issue unsuccessfully, and receives a secondary interference notification it must cease transmission immediately in the current embodiment.
(240) 8) If a station does respond to the first direct interference notification, that station will receive multiple opportunities to resolve the interference cooperatively.
(241) In some embodiments, the registry may need be to monitored and document the process so as to allow for review at a later time, allowing for an appeal process with a supervisory authority such as the FCC. If the rules are not followed, the registry may indicate directives to the stations up to and including revoking licenses, or adjusting “occupied” priority status.
(242) In one embodiment, when a dedicated “Bloom” signal is detected (for example with a unique signature and no user payload), the detecting ABS station may look in the registry to determine which other stations are in the area and in the Bloom process so as to either determine identity or confirm identity. Such an embodiment requires that the “state” of a station be updated within the Registry.
(243) In some embodiments, the “interfered with” ABS station judges an interference threshold based upon one or more of: BER impact, C/I impact, the power density of the interferer.
(244) In one embodiment, licenses are paid for by station owners based upon the licensed “Carrier to Interference ratio” (C/I) that is desired or required at that location. Having licensed a specific C/I, and when interference impinges upon them damaging the C/I beyond the level of their license, there are several embodiments operable to resolve the problem. First, and most simply, the forgoing notification procedures may be followed. Secondly, in another related embodiment, a registered station gets a fixed amount of protection, and based upon the interference level being received, the licensed ABS station is allowed to increase its transmitter power by the amount of licensed C/I degradation that are currently receiving. For example, if you purchase a license, for 40 dB C/I, you are guaranteed 40 dBi or the maximum your equipment can do, up to the permissible transmission power limit in the band. In such an embodiment, a licensed station only transmits as much power as required for the target receiver to achieve the maximum C/I it can operate at, above the noise floor plus a nominal margin amount in some embodiments. Notification may only be provided, in the current embodiment, once a licensed station reaches a “conditional maximum”. The conditional maximum is the lower of the amount that that you are interfering with someone else, or all you can transmit.
(245) In related embodiments, the C/I protection affects the license cost. For example, it might cost $1K for a 20 dB T2 license, or $2K for 25 dB T2 protection license, and so forth.
(246) In one embodiment, the allowable transmit power follows the equation:
P.sub.Allow=min(P.sub.MAX,P.sub.INTERFERENCE,P.sub.R,C/I) EQ. 8-1
(247) For example, if interference encroaches within the C/I you have purchased, the licensed station may increase its power to regain the licensed C/I. If the licensed ABS station has increased its power up to either P.sub.MAX or P.sub.INTERFERENCE, then the offending (interfering) station may be notified to cease, or to follow the interference mitigation process described previously in various embodiments.
(248) In one embodiment, if the owner of a device wants 45 dB C/I, then they need to pay more money to get cleaner spectrum. Associated with such rules they may be an occupancy requirement to retain the rights, as well as a requirement that no license may exceed the certified capability of C/I performance of the equipment being utilized for a given license. In one embodiment, one cannot purchase more protection than one's equipment can actually use. In another embodiment, the “notification” message must include, and the equipment generating the message must be able to measure the interference level at a C/I level and accuracy to which the notification indicates.
(249) In a related embodiment, any device owner may purchase what every C/I level they want, but if the device cannot measure a specific C/I with sufficient accuracy, then it is not within the rules to notify an interferer of a level of C/I and as a result such a C/I is not enforceable by that equipment. Such equipment must, in specific embodiments, be certified that it can perform the specific measurements.
(250) In one embodiment, the interference notification message is limited to a fixed interference back off step, such as 5 dB. If such a back off by the offending station does not cure the interference problem, another message may be sent.
(251) One or more of the methodologies or functions described herein may be embodied in a computer-readable medium on which is stored one or more sets of instructions (e.g., software). The software may reside, completely or at least partially, within memory and/or within a processor during execution thereof. The software may further be transmitted or received over a network.
(252) The term “computer-readable medium” should be taken to include a single medium or multiple media that store the one or more sets of instructions. The term “computer-readable medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by a machine and that cause a machine to perform any one or more of the methodologies of the present invention. The term “computer-readable medium” shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media.
(253) Embodiments of the invention have been described through functional modules at times, which are defined by executable instructions recorded on computer readable media which cause a computer, microprocessors or chipsets to perform method steps when executed. The modules have been segregated by function for the sake of clarity. However, it should be understood that the modules need not correspond to discreet blocks of code and the described functions can be carried out by the execution of various code portions stored on various media and executed at various times.
(254) It should be understood that processes and techniques described herein are not inherently related to any particular apparatus and may be implemented by any suitable combination of components. Further, various types of general purpose devices may be used in accordance with the teachings described herein. It may also prove advantageous to construct specialized apparatus to perform the method steps described herein. The invention has been described in relation to particular examples, which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will appreciate that many different combinations of hardware, software, and firmware will be suitable for practicing the present invention. Various aspects and/or components of the described embodiments may be used singly or in any combination. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the claims.