# US 9,882,759 B2 · Multiple receivers in an OFDM/OFDMA communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,882,759 B2 - Document ID: US9882759B2 - Status: Granted - Kind: B2 - Application number: 14/703,611 - Filed: 2015-05-04 - Published: 2015-08-27 - Granted: 2018-01-30 - Earliest claimed: 2012-02-06 - Assignees: Neocific, Inc. - Applicants: Neocific, Inc. - Inventors: Titus Lo; Xiaodong Li - Web page: https://patentgrep.com/patent/US9882759B2 ## CPC - H04L 27/2656: {Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation} - H04B 7/0857: {using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]} - H04B 7/0874: {using subgroups of receive antennas} - H04J 11/0079: {Acquisition of downlink reference signals, e.g. detection of cell-ID} - H04L 27/2672: {Frequency domain} - H04W 56/001: {Synchronization between nodes} - H04J 2011/0096: {Network synchronisation} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A signal receiver is configured to receive multiple time-domain input signals. A plurality of the input signals among the multiple time-domain input signals is selected and transformed into frequency-domain signals. The frequency-domain signals are shifted in phase by a negative value of a respective reference phase, and the phase-shifted signals are combined into one signal. The combined signal is then multiplied with a stored signal to generate a signal product and transformed into a time-domain signal. Peak detection is performed on the time-domain signal. ## Claims ### Claim 1 A frame detection method performed by a wireless device having a plurality of receivers, each receiver coupled to an antenna and configured to receive a signal transmitted by a same transmitting device using a frame structure comprising a plurality of frames, the signal transmitted via a propagation channel, wherein a frame of the plurality of frames comprises a plurality of subframes and a subframe comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols, the frame detection method comprising: selecting a group of OFDM signals received by the plurality of receivers, wherein each of the selected group of OFDM signals is selected based on side information comprising a spatial correlation coefficient; producing a group of cost functions, wherein each cost function is related to a differential envelope associated with one of the selected group of OFDM signals; and applying a set of criteria to each of the group of cost functions, wherein results from applying the set of criteria are used, at least in part, to determine a timing of a frame of the plurality of frames. ### Claim 2 (depends on 1) The method of claim 1, wherein the side information further comprises: a received signal strength indication (RSSI); a signal to noise ratio (SNR); an average power level; a temporal correlation coefficient; or a combination thereof. ### Claim 3 (depends on 1) The method of claim 1, wherein the wireless device is a mobile station or a base station. ### Claim 4 (depends on 1) The method of claim 1, wherein the transmitting device is a mobile station or a base station. ### Claim 5 A wireless device having a plurality of receivers, each receiver coupled to an antenna and configured to receive a signal transmitted via a propagation channel by a same transmitting device, the signal transmitted using a frame structure comprising a plurality of frames, wherein a frame of the plurality of frames comprises a plurality of subframes and a subframe comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols, the wireless device comprising: means for selecting a group of OFDM signals received by the plurality of receivers, wherein each of the selected group of OFDM signals is selected based on side information comprising a spatial correlation coefficient; means for generating a group of cost functions, wherein each cost function is related to a differential envelope associated with one of the selected group of OFDM signals; and means for applying a set of criteria to each of the group of cost functions, wherein results from applying the set of criteria are used, at least in part, to determine a timing of a frame of the plurality of frames. ### Claim 6 (depends on 5) The wireless device of claim 5, wherein said side information is a received signal strength indication (RSSI); a signal to noise ratio (SNR); an average power level; a temporal correlation coefficient; or a combination thereof. ### Claim 7 (depends on 5) The wireless device of claim 5, wherein the wireless device is a mobile station or a base station. ### Claim 8 (depends on 5) The wireless device of claim 5, wherein the transmitting device is a mobile station or a base station. ### Claim 9 A wireless device having a plurality of receivers, each receiver coupled to an antenna and configured to receive a signal transmitted via a propagation channel by a same transmitting device using a frame structure comprising a plurality of frames, wherein a frame of the plurality of frames comprises a plurality of subframes and a subframe comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols, the wireless device configured to: select a group of OFDM signals received by the plurality of receivers, wherein each of the selected group of OFDM signals is selected based on side information comprising a spatial correlation coefficient; select a group of cost functions, wherein each cost function is related to a differential envelope associated with one of the selected group of OFDM signals; and applying a set of criteria to each of the group of cost functions, wherein results from applying the set of criteria are used, at least in part, to determine a timing of a frame of the plurality of frames. ### Claim 10 (depends on 9) The wireless device of claim 9, wherein said side information is a received signal strength indication (RSSI); a signal to noise ratio (SNR); an average power level; a temporal correlation coefficient; or a combination thereof. ### Claim 11 (depends on 9) The wireless device of claim 9, wherein the wireless device is a mobile station or a base station. ### Claim 12 (depends on 9) The wireless device of claim 9, wherein the transmitting device is a mobile station or a base station.