Sub-band feedback for beamforming on downlink multiple user MIMO configurations
First Claim
1. A method in a communication network, the method comprising:
- (i) receiving, at a client device, a sounding packet from an access point device over a wireless downlink communication channel having a plurality of 20 MHz-wide subchannels, the sounding packet having a packet bandwidth that spans the plurality of 20 MHz-wide subchannels;
(ii) at the client device, identifying a subchannel block of the sounding packet, wherein the subchannel block spans only a subset of the plurality of 20 MHz-wide subchannels, and the subchannel block has a subchannel block contiguous bandwidth that is a) at least 20 MHz and b) smaller than the packet bandwidth of the sounding packet;
(iii) performing a channel estimation (a) on the subchannel block, but (b) not on any other 20 MHz-wide subchannels of the plurality of 20 MHz-wide subchannels, to determine a partial channel estimation of the downlink communication channel; and
(iv) communicating, to the access point in a feedback frame, the partial channel estimation of the downlink communication channel so that the access point can determine a steering matrix from the partial channel estimation for application to only a portion, in frequency, of an information carrying data packet, transmitted by the access point, when the information carrying data packet has a bandwidth larger than the subchannel block, wherein the feedback frame includes an indication of a bandwidth of the subchannel block to which the partial channel estimation corresponds, wherein the portion of the information carrying data packet corresponds in frequency to the subchannel block.
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Accused Products
Abstract
A method in a communication network includes an access point, using a multiple input multiple output antenna configuration, sending out a sounding packet to a plurality of client stations. The client stations determine a channel estimation of the sounding packet, but only a channel estimation of a portion of the entire sounding packet to avoid processing the entire packet. The resulting partial estimation is sent to the access point for using in transmit beamforming. In other examples, the client station sends a reverse link sounding packet over a portion a channel having a bandwidth less than the sounding packet, and from this the access point determines partial channel estimations and transmit beamforming conditions.
82 Citations
22 Claims
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1. A method in a communication network, the method comprising:
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(i) receiving, at a client device, a sounding packet from an access point device over a wireless downlink communication channel having a plurality of 20 MHz-wide subchannels, the sounding packet having a packet bandwidth that spans the plurality of 20 MHz-wide subchannels; (ii) at the client device, identifying a subchannel block of the sounding packet, wherein the subchannel block spans only a subset of the plurality of 20 MHz-wide subchannels, and the subchannel block has a subchannel block contiguous bandwidth that is a) at least 20 MHz and b) smaller than the packet bandwidth of the sounding packet; (iii) performing a channel estimation (a) on the subchannel block, but (b) not on any other 20 MHz-wide subchannels of the plurality of 20 MHz-wide subchannels, to determine a partial channel estimation of the downlink communication channel; and (iv) communicating, to the access point in a feedback frame, the partial channel estimation of the downlink communication channel so that the access point can determine a steering matrix from the partial channel estimation for application to only a portion, in frequency, of an information carrying data packet, transmitted by the access point, when the information carrying data packet has a bandwidth larger than the subchannel block, wherein the feedback frame includes an indication of a bandwidth of the subchannel block to which the partial channel estimation corresponds, wherein the portion of the information carrying data packet corresponds in frequency to the subchannel block. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus comprising:
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a transceiver configured to receive a sounding packet from an access point, the sounding packet having a packet bandwidth that spans a downlink communication channel having a plurality of 20 MHz-wide subchannels; a channel estimation circuit configured to identify a subchannel block within the sounding packet, wherein the subchannel block spans only a subset of the plurality of 20 MHz-wide subchannels, and the subchannel block has a subchannel block contiguous bandwidth that is a) at least 20 MHz and b) smaller than the packet bandwidth of the sounding packet, and perform channel estimation (i) on the subchannel block, but (ii) not on any other 20 MHz-wide subchannels of the plurality of 20 MHz-wide subchannels, to determine a partial channel estimation of a downlink communication channel; wherein the transceiver is further configured to communicate, to the access point in a feedback frame, the partial channel estimation of the downlink communication channel so that the access point can determine a steering matrix from the partial channel estimation for application to only a portion, in frequency, of an information carrying data packet when the information carrying data packet has a bandwidth larger than the subchannel block, wherein the feedback frame includes an indication of a bandwidth of the subchannel block to which the partial channel estimation corresponds, wherein the portion of the information carrying data packet corresponds in frequency to the subchannel block. - View Dependent Claims (14, 15, 16, 17, 18)
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19. An access point apparatus comprising:
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a plurality of antennas; a network interface device configured to transmit, via the plurality of antennas, a sounding packet over a wireless downlink communication channel that comprises a plurality of 20 MHz-wide subchannels, wherein the network interface device includes a steering vector controller configured to receive, from a client device, a feedback frame that includes a partial channel estimation of a subchannel block corresponding to the wireless downlink communication channel between (i) the access point and (ii) the client device, wherein the partial channel estimation corresponds to only a subset of the plurality of 20 MHz-wide subchannels, the feedback frame does not include channel estimation information for any other 20 MHz-wide subchannels in the wireless downlink communication channel, the subchannel block corresponds to only the subset of the 20 MHz-wide subchannels and has a contiguous bandwidth of at least 20 MHz, and the steering vector controller is configured to use the partial channel estimation to identify a steering matrix for use in communicating on the wireless downlink communication channel between (i) the access point and (ii) the client device, and a spatial steering controller configured to apply the identified steering matrix to only a portion, in frequency, of an information carrying packet, wherein the portion, in frequency, of the information carrying packet corresponds, in frequency, to the subchannel block. - View Dependent Claims (20, 21, 22)
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Specification