# US 11,451,275 B2 · System and method for distributed antenna wireless communications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,275 B2 - Document ID: US11451275B2 - Status: Granted - Kind: B2 - Application number: 17/586,765 - Filed: 2022-01-27 - Published: 2022-05-19 - Granted: 2022-09-20 - Earliest claimed: 2004-04-02 - Assignees: Rearden, LLC - Applicants: Rearden, LLC - Inventors: Antonio Forenza; Stephen G. Perlman - Web page: https://patentgrep.com/patent/US11451275B2 ## CPC - H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems - H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting - H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]} - H04B 7/0417: Feedback systems - H04B 7/0452: Multi-user MIMO systems - H04B: TRANSMISSION ## Abstract A system and method are described for distributed antenna wireless communications. For example, a method implemented within a wireless transmission system comprised of a plurality of wireless client devices and a plurality of distributed antennas is described comprising: computing channel state information (CSI) for wireless communication channels between the plurality of base distributed antennas and the wireless client devices; computing precoding weights from the channel state information; precoding data using the precoding weights prior to wireless transmission from the plurality of distributed antennas to the wireless client devices; and wirelessly transmitting the precoded data from the distributed antennas to each of the wireless client devices, wherein the precoding causes radio frequency interference between the plurality of base stations but simultaneously generating a plurality of non-interfering radio frequency user channels between the plurality of distributed antennas and the plurality of wireless client devices. ## Claims ### Claim 1 A wireless transceiver station configured to create a plurality of concurrent and independent orthogonal frequency-division multiplexing (“OFDM”) wireless links between the wireless transceiver station and a plurality of user devices within a same frequency band, the wireless links formed over multipath downlink or uplink channels; wherein the wireless transceiver station is configured to create the plurality of concurrent and independent OFDM wireless links using a number of wireless transceiver station antennas equal to more than ten times a number of at least one user device's antennas configured to communicate over at least one of the uplink channels of the concurrent and independent OFDM wireless links. ### Claim 2 (depends on 1) The system as in claim 1 wherein the wireless links have a specified wavelength and wherein two or a subset of the antennas at the wireless transceiver station are spaced apart less than the specified wavelength. ### Claim 3 (depends on 1) The system as in claim 1 wherein two or a subset of the wireless transceiver station antennas are cross-polarized. ### Claim 4 (depends on 1) The system as in claim 1 wherein the wireless transceiver station is equipped with more than 10 times the number of antennas configured to communicate over at least one of the concurrent and independent OFDM wireless links on each user device. ### Claim 5 (depends on 1) The system as in claim 1 wherein the wireless transceiver station is configured to communicate with user devices that are equipped with multiple antennas configured to communicate over at least one of the concurrent and independent OFDM wireless links. ### Claim 6 (depends on 1) The system as in claim 1 wherein the wireless transceiver station is configured to communicate with user devices that are equipped with between two and four antennas configured to communicate over at least one of the concurrent and independent OFDM wireless links. ### Claim 7 (depends on 1) The system as in claim 1 wherein the wireless transceiver station is configured to communicate with user devices that are equipped with a single antenna configured to communicate over at least one of the concurrent and independent OFDM wireless links. ### Claim 8 A wireless transceiver station configured to create a plurality of concurrent and independent orthogonal frequency-division multiplexing (“OFDM”) wireless links between the wireless transceiver station and a plurality of user devices within a same frequency band, the wireless links formed over multipath downlink or uplink channels; wherein the wireless transceiver station is configured to create the plurality of concurrent and independent OFDM wireless links using a number of wireless transceiver station antennas equal to more than ten times a number of antennas configured to communicate over at least one of the concurrent and independent OFDM wireless links of at least one user device. ### Claim 9 (depends on 8) The system as in claim 8 wherein the wireless transceiver station is configured to communicate with user devices that are equipped with multiple antennas configured to communicate over at least one of the concurrent and independent OFDM wireless links. ### Claim 10 (depends on 8) The system as in claim 8 wherein the wireless transceiver station is configured to communicate with user devices that are equipped with between two and four antennas configured to communicate over at least one of the concurrent and independent OFDM wireless links. ### Claim 11 (depends on 8) The system as in claim 8 wherein the wireless transceiver station is configured to communicate with user devices that are equipped with a single antenna configured to communicate over at least one of the concurrent and independent OFDM wireless links. ### Claim 12 (depends on 8) The system as in claim 8 wherein the antennas on the wireless transceiver station are directional antennas. ### Claim 13 (depends on 8) The system as in claim 8 wherein the antennas on the wireless transceiver station are a phased array implementing beam-steering. ### Claim 14 (depends on 8) The system as in claim 8 wherein the wireless transceiver station is configured to employ beamforming, to increase link reliability or channel capacity, wherein beamforming comprises creating multiple simultaneous beams at once. ### Claim 15 (depends on 8) The system as in claim 8 wherein the wireless transceiver station is equipped with more than 10 times the number of antennas configured for OFDM wireless links on each user device. ### Claim 16 A wireless transceiver station configured to create a plurality of concurrent and independent orthogonal frequency-division multiplexing (“OFDM”) wireless links between the wireless transceiver station and a plurality of user devices within a same frequency band, the wireless links formed over multipath downlink or uplink channels; wherein the wireless transceiver station is configured to create the plurality of concurrent and independent OFDM wireless links using a number of wireless transceiver station antennas equal to more than ten times a number of antennas configured to communicate over at least one of the uplink channels of the concurrent and independent OFDM wireless links of at least one user device. ### Claim 17 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to exploit channel reciprocity by estimating an uplink channel state information (CSI) between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices and using it to derive a downlink CSI. ### Claim 18 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to estimate a CSI between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices by using pilot tones, channel sounding or training signals. ### Claim 19 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to estimate a CSI between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices by training signals that are orthogonal. ### Claim 20 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to store a CSI estimate between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices in a channel characterization matrix. ### Claim 21 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to store a CSI estimate between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices in a channel characterization matrix comprised of phase and amplitude of the channel. ### Claim 22 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to direct user devices to transmit training signals. ### Claim 23 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to direct user devices to transmit training signals that are synchronized. ### Claim 24 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to update a CSI estimate between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices continually or periodically. ### Claim 25 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to update a CSI estimate between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices as the user devices move from one location to another. ### Claim 26 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to create the data links via precoding based on a plurality of CSI estimates between the plurality of antennas on the wireless transceiver station and one or more of the antennas of the plurality of user devices. ### Claim 27 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to divide the user devices into groups. ### Claim 28 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to divide user devices into groups and schedule different groups of users by cycling between groups. ### Claim 29 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to divide the user devices into groups and assign the same or different levels of bandwidth to the user devices. ### Claim 30 (depends on 16) The system as in claim 16 wherein the wireless transceiver station is configured to divide the user devices into groups and schedule different groups based on relative proximity between the user devices.