Source: http://www.google.ca/patents/US9119217
Timestamp: 2018-01-21 03:04:06
Document Index: 518010707

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US9119217 - Interference management in a wireless communication system using frequency ... - Google Patents
Interference that occurs during wireless communication may be managed by determination of a selected transmit waveform exhibiting a preferred channel quality. A method, apparatus and medium of communication determine a transmit waveform from among a plurality of allocated waveforms of an unplanned access...http://www.google.ca/patents/US9119217?utm_source=gb-gplus-sharePatent US9119217 - Interference management in a wireless communication system using frequency selective transmission
Publication number US9119217 B2
Application number US 14/263,607
Also published as CA2706682A1, CN101926139A, CN101926139B, EP2243306A2, EP2243306B1, US8948095, US20090252099, US20140233416, WO2009070602A2, WO2009070602A3
Publication number 14263607, 263607, US 9119217 B2, US 9119217B2, US-B2-9119217, US9119217 B2, US9119217B2
Inventors Peter J. Black, Mingxi Fan, Sarut Vanichpun, Mehmet Yavuz
Patent Citations (307), Non-Patent Citations (21), Classifications (5), Legal Events (1)
US 9119217 B2
Interference that occurs during wireless communication may be managed by determination of a selected transmit waveform exhibiting a preferred channel quality. A method, apparatus and medium of communication determine a transmit waveform from among a plurality of allocated waveforms of an unplanned access point to an associated access terminal. The transmit waveform exhibiting a highest channel quality with an associated access terminal over others of the plurality of allocated waveforms is determined. Signals are transmitted according to the transmit waveform from the unplanned access point to the associated access terminal.
determining a transmit waveform from among a plurality of N allocated waveforms of a first communication node to a second communication node, wherein the plurality of N allocated waveforms are formed from coefficients of an N-tap channel filter with each coefficient set being derived from a specific row in an N×N digital Fourier transform matrix, the transmit waveform exhibiting a highest channel quality in the presence of interference with the second communication node over others of the plurality of allocated waveforms, and wherein the channel quality with the second communication node is tested for each of the plurality of allocated waveforms; and
transmitting signals according to the transmit waveform from the first communication node to the second communication node.
determining a default waveform as the transmit waveform from among the plurality of allocated waveforms; and
designating a different one of the plurality of allocated waveforms as the transmit waveform when one of the plurality of allocated waveforms exhibits a higher channel quality.
testing the channel quality with the second communication node of each of the plurality of allocated waveforms of the first communication node; and
selecting the transmit waveform as one from among the plurality of allocated waveforms exhibiting the highest channel quality.
4. The method of claim 3, wherein the testing comprises for each of the plurality of allocated waveforms:
transmitting a signal to the second communication node using one of the plurality of allocated waveforms; and
receiving an indication of channel quality of the signal from the second communication node.
5. The method of claim 1, further comprising repeating the determining of the transmit waveform based on an update period.
6. The method of claim 1, further comprising repeating the determining of the transmit waveform based on deviation of a current channel quality by a channel quality degradation threshold from the highest channel quality.
7. The method of claim 1, wherein the first communication node comprises an unplanned access point, and the second communication node comprises an associated access terminal.
an interference controller configured to determine a transmit waveform from among a plurality of N allocated waveforms of a first communication node to a second communication node, wherein the plurality of N allocated waveforms are formed from coefficients of an N-tap channel filter with each coefficient set being derived from a specific row in an N×N digital Fourier transform matrix, the transmit waveform exhibiting a highest channel quality in the presence of interference with the second communication node over others of the plurality of allocated waveforms, and wherein the channel quality with the second communication node is tested for each of the plurality of allocated waveforms; and
a communication controller configured to transmit signals according to the transmit waveform from the first communication node to the second communication node.
9. The apparatus of claim 8, wherein the interference controller is further configured to determine a default waveform as the transmit waveform from among the plurality of allocated waveforms, and to designate a different one of the plurality of allocated waveforms as the transmit waveform when one of the plurality of allocated waveforms exhibits a higher channel quality.
10. The apparatus of claim 8, wherein the inference controller is further configured to test the channel quality with the second communication node of each of the plurality of allocated waveforms of the first communication node, and to select the transmit waveform as one from among the plurality of allocated waveforms exhibiting the highest channel quality.
11. The apparatus of claim 10, wherein the communication controller is further configured, for each of the plurality of allocated waveforms, to transmit a signal to the second communication node using one of the plurality of allocated waveforms, and to receive an indication of channel quality of the signal from the second communication node.
12. The apparatus of claim 8, wherein the interference controller is further configured to repeat the determining of the transmit waveform based on an update period.
13. The apparatus of claim 8, wherein the interference controller is further configured to repeat the determining of the transmit waveform based on deviation of a current channel quality by a channel quality degradation threshold from the highest channel quality.
14. The apparatus of claim 8, wherein the first communication node comprises an unplanned access point, and the second communication node comprises an associated access terminal.
means for determining a transmit waveform from among a plurality of N allocated waveforms of a first communication node to a second communication node, wherein the plurality of N allocated waveforms are formed from coefficients of an N-tap channel filter with each coefficient set being derived from a specific row in an N×N digital Fourier transform matrix, the transmit waveform exhibiting a highest channel quality in the presence of interference with the second communication node over others of the plurality of allocated waveforms, and wherein the channel quality with the second communication node is tested for each of the plurality of allocated waveforms; and
means for transmitting signals according to the transmit waveform from the first communication node to the second communication node.
means for determining a default waveform as the transmit waveform from among the plurality of allocated waveforms; and
means for designating a different one of the plurality of allocated waveforms as the transmit waveform when one of the plurality of allocated waveforms exhibits a higher channel quality.
17. The apparatus of claim 15, wherein the means for determining comprises:
means for testing the channel quality with the second communication node of each of the plurality of allocated waveforms of the first communication node; and
means for selecting the transmit waveform as one from among the plurality of allocated waveforms exhibiting the highest channel quality.
18. The apparatus of claim 17, wherein the means for testing, for each of the plurality of allocated waveforms, comprises:
means for transmitting a signal to the second communication node using one of the plurality of allocated waveforms; and
means for receiving an indication of channel quality of the signal from the second communication node.
19. The apparatus of claim 15, further comprising means for repeating the determining of the transmit waveform based on an update period.
20. The apparatus of claim 15, further comprising means for repeating the determining of the transmit waveform based on deviation of a current channel quality by a channel quality degradation threshold from the highest channel quality.
21. The apparatus of claim 15, wherein the first communication node comprises an unplanned access point, and the second communication node comprises an associated access terminal.
22. A non-transitory computer-readable medium comprising codes for causing a computer to:
determine a transmit waveform from among a plurality of N allocated waveforms of a first communication node to a second communication node, wherein the plurality of N allocated waveforms are formed from coefficients of an N-tap channel filter with each coefficient set being derived from a specific row in an N×N digital Fourier transform matrix, the transmit waveform exhibiting a highest channel quality in the presence of interference with the second communication node over others of the plurality of allocated waveforms, and wherein the channel quality with the second communication node is tested for each of the plurality of allocated waveforms; and
transmit signals according to the transmit waveform from the first communication node to the second communication node.
23. The non-transitory computer-readable medium of claim 22, wherein the codes for causing the computer to determine comprise codes for causing the computer to:
determine a default waveform as the transmit waveform from among the plurality of allocated waveforms; and
designate a different one of the plurality of allocated waveforms as the transmit waveform when one of the plurality of allocated waveforms exhibits a higher channel quality.
24. The non-transitory computer-readable medium of claim 22, wherein the codes for causing the computer to determine comprise codes for causing the computer to:
test the channel quality with the second communication node of each of the plurality of allocated waveforms of the first communication node; and
select the transmit waveform as one from among the plurality of allocated waveforms exhibiting the highest channel quality.
25. The non-transitory computer-readable medium of claim 24, wherein the codes for causing the computer to test comprise, for each of the plurality of allocated waveforms, codes for causing the computer to:
transmit a signal to the second communication node using one of the plurality of allocated waveforms; and
receive an indication of channel quality of the signal from the second communication node.
26. The non-transitory computer-readable medium of claim 22, further comprising codes for causing the computer to repeat the determining of the transmit waveform based on an update period.
27. The non-transitory computer-readable medium of claim 22, further comprising codes for causing the computer to repeat the determining of the transmit waveform based on deviation of a current channel quality by a channel quality degradation threshold from the highest channel quality.
28. The non-transitory computer-readable medium of claim 22, wherein the first communication node comprises an unplanned access point, and the second communication node comprises an associated access terminal.
The present Application for Patent is a Continuation of and claims priority to patent application Ser. No. 12/276,906 entitled “INTERFERENCE MANAGEMENT IN A WIRELESS COMMUNICATION SYSTEM USING FREQUENCY SELECTIVE TRANSMISSION” filed Nov. 24, 2008, assigned to the assignee hereof and hereby expressly incorporated by reference herein, and which claims the benefit of and priority to the following commonly owned applications:
U.S. Provisional Patent Application No. 60/990,541, filed Nov. 27, 2007;
U.S. Provisional Patent Application No. 60/990,547, filed Nov. 27, 2007;
U.S. Provisional Patent Application No. 60/990,459, filed Nov. 27, 2007;
U.S. Provisional Patent Application No. 60/990,513, filed Nov. 27, 2007;
U.S. Provisional Patent Application No. 60/990,564, filed Nov. 27, 2007; and
U.S. Provisional Patent Application No. 60/990,570, filed Nov. 27, 2007;
the disclosure of each of which is hereby incorporated by reference herein.
U.S. patent application Ser. No. 12/276,894, entitled “INTERFERENCE MANAGEMENT IN A WIRELESS COMMUNICATION SYSTEM USING BEAM AND NULL STEERING,”;
U.S. patent application Ser. No. 12/276,897, entitled “INTERFERENCE MANAGEMENT IN A WIRELESS COMMUNICATION SYSTEM USING OVERHEAD CHANNEL POWER CONTROL,”;
U.S. patent application Ser. No. 12/276,916, entitled “INTERFERENCE MANAGEMENT IN A WIRELESS COMMUNICATION SYSTEM USING ADAPTIVE PATH LOSS ADJUSTMENT,”;
U.S. patent application Ser. No. 12/276,882, entitled “INTERFACE MANAGEMENT IN A WIRELESS COMMUNICATION SYSTEM USING SUBFRAME TIME REUSE,”; and
U.S. patent application Ser. No. 12/276,932, entitled “INTERFACE MANAGEMENT IN WIRELESS COMMUNICATION SYSTEM USING HYBRID TIME REUSE,”;
The disclosure relates to managing interference through determination of an optimal transmit waveform from an access point by using a proper frequency shaping (e.g., filtering). For a given access point, the transmitted waveform would be filtered by an optimal transmit filter selected from one of the allowed set of filters. By choosing the optimal waveform the perceived interference at a neighboring access terminal is reduced. In one exemplary embodiment, a method of communication includes determining an optimized transmit filter of an unplanned access point to an associated access terminal during a call therebetween. When the optimized transmit filter is determined, the overhead channel is transmitted from the unplanned access point with the optimized transmit filter to an associated access terminal.
In another exemplary embodiment, an apparatus for communication includes an interference controller configured to determine an optimized transmit filter to an associated access terminal during a call therebetween. When the optimized transmit filter has been determined, a communication controller transmits the overhead channel from the unplanned access point using the optimized transmit filter to the associated access terminal.
Referring now to FIG. 7 and with further reference to FIGS. 5A-5B, operations relating to the use of beam-steering and null-steering to address jamming and negative geometries will be described in more detail. The present exemplary embodiment uses methods and apparatus to prevent jamming and negative geometries using beam steering and null steering in unplanned base station deployments with restricted access.
(The function ƒ(·) can be determined through offline simulations or tests.) Then, as represented by block 816, the optimal Ect value is determined as:
T2P OPTIMAL = Ect OPTIMAL Ecp OPTIMAL .
Ecp = Ect FILTERED / T 2 P OPTIMAL .
Ecp = max [ Ect FILTERED / T 2 P OPTIMAL , Ecp DEFAULT ] .
T2POPTIMAL depends on particular traffic configuration (rate, coding etc.). For example, if two users are performing voice calls with same rate vocoders, they would have same T2POPTIMAL. However if there is another user performing data transfer (e.g., 1xRTT data transfer at 153 kbps) it would require a different T2POPTIMAL. Once the T2POPTIMAL is determined for given user (based on its traffic type), then the algorithm automatically adjusts Ecp. The above algorithm is specified for one user. If there are multiple users, then the algorithm may result in different Ecp values for each user. However, overhead channels are common to all users and we can only have one Ecp setting. Thus the algorithm could be generalized to a multiple users case. By way of example, an “optimal” Ecp; for each user (i=1, . . . , N) in the system could be found as described above and then an actual Ecp could be decided as max(Ecp1, . . . , EcpN). Another option could be to find the optimal Ecp such that total power transmitted as overhead and traffic to all users is minimized. This would mean a modification of the calculation of box 814 to:
In the above algorithm, Δ1 and Δ2 are hysteresis parameters used to prevent fast fluctuations of Ecp. Furthermore, in order to prevent abrupt changes of Ecp equations above may be modified, in one exemplary embodiment, to let the Ecp correction to be performed more slowly. Lastly, other overhead channels (e.g., page, sych) can be adjusted based on the pilot power level (i.e., their relative power level with respect to pilot power level can be kept constant).
h 1 [ n ] = δ [ n ] + δ [ n - 2 ] + δ [ n - 4 ] h 2 [ n ] = δ [ n ] + ⅇ j 2 π 3 δ [ n - 2 ] + ⅇ - j 2 π 3 δ [ n - 4 ] = δ [ n ] + ( - 0.5 + j 0.866 ) · δ [ n - 2 ] + ( - 0.5 - j 0.866 ) · δ [ n - 4 ] h 3 [ n ] = δ [ n ] + ⅇ - j 2 π 3 δ [ n - 2 ] + ⅇ j 2 π 3 δ [ n - 4 ] == δ [ n ] + ( - 0.5 - j 0.866 ) · δ [ n - 2 ] + ( - 0.5 + j 0.866 ) · δ [ n - 4 ] where exp ( j x ) = cos ( x ) + j sin ( x ) .
For stable system operation on the uplink UL, RoT needs to be controlled. Typically, RoT is controlled to be around 5 dB and higher. High RoT values can cause significant performance degradation. For example, in FIG. 5B for the two neighboring cells formed by femto nodes 510A and 510B, high RoT caused by access terminal 520D at femto node 510A results in performance degradation for associated access terminal 520C. One specific interfering scenario occurs when neighbor access terminal 520D has bursty uplink UL traffic and exhibits overly high power levels (e.g., in close proximity) at femto node 510A. Accordingly, during high rate data uplink UL bursts from access terminal 520D, the RoT at femto node 510A goes above 20 dB. Furthermore, the uplink UL power control mechanism in CDMA systems (e.g., CDMA2000, WCDMA, 1xEV-DO) is designed to combat this type of interference scenarios. However due to excessive variation in RoT, the mechanism may take some time for femto node 510A to power control associated access terminal 520C to overcome the interference caused by non-associated access terminal 520D. Meanwhile the signal-to-interference ratio (SIR) of associated access terminal 520C falls below required levels resulting in consecutive packet errors on the uplink UL from associated access terminal 520C to home femto node 510A.
RoT ( n ) = [ Ioc ( n ) + Ior ( n ) + No ( n ) ] / No ( n ) and Ior ( n ) = ∑ i ∈ InCell Ec i ( n )
As represented by block 1108, a total received signal strength Io(n) is measured. The total received signal strength Io(n) is the total received power received at the femto node from all wireless devices for whom the femto node is in their active set and from all wireless devices for whom the femto node is not in their active set. As represented by block 1112, the in-cell (associated access terminal) interference level Ior, which is the total received power received at the femto node from all wireless devices for whom femto node is in their active set, is computed. The computed in-cell interference level can be expressed as:
max ( Ecp ( n ) Nt ( n ) ) _ = max i ∈ in - cell access terminals [ filter ( Ecp i ( n ) Nt i ( n ) ) ]
The teachings herein may be incorporated into various types of communication systems and/or system components. In some aspects, the teachings herein may be employed in a multiple-access system capable of supporting communication with multiple users by sharing the available system resources (e.g., by specifying one or more of bandwidth, transmit power, coding, interleaving, and so on). For example, the teachings herein may be applied to any one or combinations of the following technologies: Code Division Multiple Access (“CDMA”) systems, Multiple-Carrier CDMA (“MCCDMA”), Wideband CDMA (“W-CDMA”), High-Speed Packet Access (“HSPA,” “HSPA+”) systems, Time Division Multiple Access (“TDMA”) systems, Frequency Division Multiple Access (“1-DMA”) systems, Single-Carrier FDMA (“SC-FDMA”) systems, Orthogonal Frequency Division Multiple Access (“OFDMA”) systems, or other multiple access techniques. A wireless communication system employing the teachings herein may be designed to implement one or more standards, such as IS-95, cdma2000, IS-856, W-CDMA, TDSCDMA, and other standards. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (“UTRA)”, cdma2000, or some other technology. UTRA includes W-CDMA and Low Chip Rate (“LCR”). The cdma2000 technology covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (“GSM”). An OFDMA network may implement a radio technology such as Evolved UTRA (“E-UTRA”), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (“UMTS”). The teachings herein may be implemented in a 3GPP Long Term Evolution (“LTE”) system, an Ultra-Mobile Broadband (“UMB”) system, and other types of systems. LTE is a release of UMTS that uses E-UTRA. Although certain aspects of the disclosure may be described using 3GPP terminology, it is to be understood that the teachings herein may be applied to 3GPP (Rel99, Rel5, Rel6, Rel7) technology, as well as 3GPP2 (1xRTT, 1xEV-DO RelO, RevA, RevB) technology and other technologies.
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International Classification H04L25/03, H04W4/00, H04W72/08
Cooperative Classification H04L25/03343, H04W72/085
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BLACK, PETER J.;FAN, MINGXI;VANICHPUN, SARUT;AND OTHERS;SIGNING DATES FROM 20081222 TO 20090603;REEL/FRAME:033499/0369