Cooperative mimo in multicell wireless networks

Abstract

A method and system for cooperative multiple-input multiple output (MIMO) transmission operations in a multicell wireless network. Under the method, antenna elements from two or more base stations are used to form an augmented MIMO antenna array that is used to transmit and received MIMO transmissions to and from one or more terminals. The cooperative MIMO transmission scheme supports higher dimension space-time-frequency processing for increased capacity and system performance.

What is claimed is: 
     
         1 . A method comprising:
 employing antenna elements from a plurality of base stations to support joint cooperative multiple-input multiple-output (MIMO) transmissions in a wireless network, wherein the joint cooperative MIMO transmissions are orthogonal frequency division multiple access (OFDMA) MIMO transmissions;   replicating a data stream received from an information source;   forwarding the replication of the data stream to each base station of the plurality of base stations;   performing antenna signal processing operations at each base station of the plurality of base stations on the replication of the data stream it receives to generate antenna signals;   transmitting the antenna signals over selected antenna elements of the antenna elements at each base station of the plurality of base stations to form the joint cooperative MIMO transmissions; and   encoding, at respective base stations of the plurality of base stations, the replication of the data stream using one of space-time coding, space-frequency coding, space-time-frequency coding, and spatial multiplexing to establish the joint cooperative MIMO transmissions.   
     
     
         2 . The method of  claim 1 , wherein the encoded joint cooperative MIMO transmissions include subscriber MIMO channel information. 
     
     
         3 . The method of  claim 1 , wherein the space-time coding comprises space-time trellis coding. 
     
     
         4 . The method of  claim 1 , wherein the space-time coding comprises space-time block coding. 
     
     
         5 . The method of  claim 1 , further comprising:
 encoding the joint cooperative MIMO transmissions using space-time coding with delay diversity.   
     
     
         6 . The method of  claim 1 , wherein the joint cooperative MIMO transmissions include downlink transmission s from the plurality of base stations to terminals and uplink transmissions from the terminals to the plurality of base stations. 
     
     
         7 . The method of  claim 1 , further comprising:
 performing spatial beamforming for selected ones of the joint cooperative MIMO transmissions.   
     
     
         8 . The method of  claim 7 , wherein the spatial beamforming is performed in combination with one of space-time, space-frequency and space-time-frequency coding of the selected ones of the joint cooperative MIMO transmissions. 
     
     
         9 . The method of  claim 1 , further comprising:
 transmitting the joint cooperative MIMO transmissions to at least two terminals simultaneously.   
     
     
         10 . The method of  claim 9 , further comprising:
 performing spatial beamforming on the joint cooperative MIMO transmissions such that MIMO transmissions are directed toward intended users while spatial nulling is effected toward unintended users.   
     
     
         11 . The method of  claim 1 , further comprising:
 decoding, jointly, uplink MIMO transmissions received from multiple terminals.   
     
     
         12 . The method of  claim 1 , further comprising:
 decoding, jointly, downlink MIMO transmissions received at multiple terminals.   
     
     
         13 . The method of  claim 1 , further comprising:
 decoding, separately, uplink MIMO transmissions received from multiple terminals.   
     
     
         14 . The method of  claim 1 , further comprising:
 encoding, jointly, downlink MIMO transmissions sent to multiple terminals.   
     
     
         15 . The method of  claim 14 , further comprising:
 decoding a jointly encoded downlink MIMO transmission at a terminal of the multiple terminals; and   keeping portions of data sent via the jointly encoded downlink MIMO transmission intended for the terminal, while discarding other portions of the data that are not intended for the terminal.   
     
     
         16 . The method of  claim 14 , further comprising:
 separately decoding, separately, the jointly encoded downlink transmissions at each of the multiple terminals.   
     
     
         17 . The method of  claim 1 , further comprising:
 synchronizing performance of the antenna signal processing operations at the plurality of base stations such that the antenna signals are transmitted over the selected antenna elements at different base stations of the plurality of base stations in synchrony.   
     
     
         18 . The method of  claim 1 , further comprising:
 performing the joint cooperative MIMO transmissions to facilitate terminal handoff between wireless network cells or sectors.   
     
     
         19 . The method of  claim 1 , further comprising:
 performing MIMO encoding on another data stream to be transmitted over a corresponding joint cooperative MIMO channel, the MIMO encoding producing a respective set of encoded data sequences for each base station of the plurality of base stations;   sending to each base station of the plurality of base stations the respective set of encoded data sequences produced therefor;   performing other antenna signal processing operations to generate other antenna signals at each base station of the plurality of base stations in view of the respective sets of encoded data sequences received thereby; and   transmitting the other antenna signals over corresponding antenna elements of the antenna elements at each base station of the plurality of base stations to transmit the another data stream over the corresponding joint cooperative MIMO channel.   
     
     
         20 . The method of  claim 19 , further comprising:
 synchronizing the performance of the other antenna signal processing operations at the plurality of base stations such that the other antenna signals are transmitted over the selected antenna elements at different base stations of the plurality of base stations in synchrony.   
     
     
         21 . A multicell wireless network, comprising:
 a plurality of base stations each associated with a respective cell and having a respective antenna array including at least one antenna element;   a joint cooperative multiple-input multiple-output (MIMO) transmission mechanism that employs selected antenna elements from the plurality of base stations to:
 form an augmented antenna array used to support joint cooperative MIMO transmissions over the wireless network, wherein the joint cooperative MIMO transmissions are orthogonal frequency division multiple access (OFDMA) MIMO transmissions; and 
 encode, at respective base stations of the plurality of base stations, the replication of the data stream using one of space-time coding, space-frequency coding, space-time-frequency coding, and spatial multiplexing to establish the joint cooperative MIMO transmissions; 
   a data replicator to:
 replicate a data stream received from an information source; and 
 forward the replication of the data stream to each base station of the plurality of base stations; and 
   a set of antenna signal processing components at each base station of the plurality of base stations to perform antenna signal processing operations on the data stream it receives to generate antenna signals, wherein the antenna signals are transmitted over the selected antenna elements to form a joint cooperative MIMO transmission at each base station of the plurality of base stations.   
     
     
         22 . The multicell wireless network of  claim 21 , wherein the encoded joint cooperative MIMO transmissions include subscriber MIMO channel information. 
     
     
         23 . The multicell wireless network of  claim 21 , wherein the space-time coding comprises space-time trellis coding. 
     
     
         24 . The multicell wireless network of  claim 21 , wherein the space-time coding comprises space-time block coding. 
     
     
         25 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism encodes the joint cooperative MIMO transmissions using space-time coding with delay diversity. 
     
     
         26 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmissions include downlink transmissions from the plurality of base stations to terminals and uplink transmissions from the terminals to the plurality of base stations. 
     
     
         27 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism performs spatial beam forming for selected ones of the joint cooperative MIMO transmissions. 
     
     
         28 . The multicell wireless network of  claim 27 , wherein the joint cooperative MIMO transmission mechanism performs the spatial beamforming in combination with one of space-time, space-frequency and space-time-frequency coding of the selected ones of the joint cooperative MIMO transmissions. 
     
     
         29 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism performs transmitting the joint cooperative MIMO transmissions to at least two terminals simultaneously. 
     
     
         30 . The multicell wireless network of  claim 29 , wherein the joint cooperative MIMO transmission mechanism further perforins spatial beamforming on the joint cooperative MIMO transmissions such that MIMO transmissions are directed toward intended users while spatial nulling is effected toward unintended users. 
     
     
         31 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism further performs jointly decoding uplink MIMO transmissions received from multiple terminals. 
     
     
         32 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism further performs separately decoding uplink MIMO transmissions received from multiple terminals. 
     
     
         33 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism further performs jointly encoding downlink MIMO transmissions sent to multiple terminals. 
     
     
         34 . The multicell wireless network of  claim 21 , further comprising:
 a synchronizing mechanism to synchronize the antenna signal processing operation s at the plurality of base stations such that the antenna signals are transmitted over the selected antenna elements at different base stations of the plurality of base stations in synchrony.   
     
     
         35 . The multicell wireless network of  claim 21 , further comprising: a master encoder to:
 perform MIMO encoding on another data stream to be transmitted over a corresponding joint cooperative MIMO channel, the MIMO encoding producing a respective set of encoded data sequences for each base station of the plurality of base stations; and   send to each base station of the plurality of base stations the respective set of encoded data sequences produced therefor; and   a set of other antenna signal processing components at each base station of the plurality of base stations to perform other antenna signal processing operations on the respective sets of encoded data sequences received thereby to generate other antenna signals,   wherein the other antenna signals are transmitted over the selected antenna elements at each base station of the plurality of base stations to form the joint cooperative MIMO transmissions over the corresponding joint cooperative MIMO channel.   
     
     
         36 . The multicell wireless network of  claim 35 , further comprising:
 a synchronizing mechanism to synchronize the other antenna signal processing operations at the plurality of base stations such that the other antenna signals are transmitted over the selected antenna elements at different base stations of the plurality of base stations in synchrony.   
     
     
         37 . The multicell wireless network of  claim 21 , wherein the joint cooperative MIMO transmission mechanism performs the joint cooperative MIMO transmissions to facilitate terminal handoff between wireless network cells or sectors.