Virtual mimo communication system
View Patent ↗The present invention provides an effective way to create a virtual MIMO transmission system using mobile terminals that have only one transmit path and antenna. This is accomplished by assigning mobile terminals to a group and assigning certain shared resources and user-specific resources to those mobile terminals in the group. In a synchronized fashion, the mobile terminals will provide uplink transmission in concert, as if they were a single entity having multiple transmission paths and antennas. Preferably, the shared resources bear on how the data is transmitted, and the user-specific resources relate to pilot signals. The data transmitted may be encoded in any number of ways, and in one embodiment, the mobile terminals may relay their information to each other, such that uplink transmissions can incorporate STTD decoding or other space-time codes. The invention is applicable to virtually any multiple access technology, including OFDM, TDMA, and CDMA, preferably synchronous CDMA.
1. A method for facilitating cooperative uplink transmission comprising:
a) identifying a group of mobile terminals to provide cooperative uplink transmissions;
b) assigning a common resource via downlink transmissions to each mobile terminal in the group of mobile terminals, such that the common resource for each mobile terminal is the same and used for uplink transmission; and
c) assigning a different unique resource via downlink transmissions to each mobile terminal, such that the unique resource for each of the mobile terminals is different and used for the uplink transmission, wherein each of the mobile terminals in the group of mobile terminals concurrently uses the common resource and a corresponding unique resource during the uplink transmissions to provide a virtual multiple input multiple output uplink transmission.
2. The method of claim 1 wherein the common resource is an OFDM sub-carrier block in the time and frequency domain, such tat the mobile terminals will concurrently transmit data in certain sub-carriers in the sub-carrier block.
3. The method of claim 2 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal assigned to at least one of the sub-carriers in the sub-carrier block, such that no two mobile terminals in the group of mobile terminals transmit the unique pilot information in a common sub-carrier.
4. The method of claim 2 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal, which is created in part from pilot information for at least one other mobile terminal in the group of mobile terminals and assigned to at least one of the sub-carriers in the sub-carrier block.
5. The method of claim 4 wherein the unique pilot signal for each mobile terminal is created using STTD coding from the pilot information for a corresponding mobile terminal and the pilot information for at least one other mobile terminal in the group of mobile terminals.
6. The method of claim 1 wherein the common resource is at least one of a CDMA spreading code and a CDMA scrambling code, such that the mobile terminals will concurrently transmit data spread by at least one of the CDMA spreading and CDMA scrambling codes.
7. The method of claim 6 wherein each unique resource is a unique code, such that the mobile terminals will concurrently transmit data further spread or scrambled by the unique code.
8. The method of claim 1 further comprising concurrently receiving the uplink transmission from each of the mobile terminals in the group of mobile terminals via a plurality of antennas.
9. The method of claim 1 wherein at least one of the mobile terminals in the group of mobile terminals has a plurality of antennas and a plurality of unique resources are assigned to the at least one mobile terminal having the plurality of antennas.
10. The method of claim 1 wherein the common resource is used for transmitting data and the unique resources we used for transmitting pilot information.
11. The method of claim 1 wherein data transmitted from each of the mobile terminals includes data corresponding to the mobile terminal transmitting the data.
12. The method of claim 11 further comprising receiving the uplink transmission from the mobile terminals via a plurality of antennas and decoding the data transmitted from each of the mobile terminals using parallel decoding.
13. The method of claim 1 wherein data in the uplink transmission for a mobile terminal in the group of mobile terminals includes data from another mobile terminal in the group of mobile terminals.
14. The method of claim 13 wherein the data is encoded using STTD encoding.
15. The method of claim 14 further comprising receiving the uplink transmission from the mobile terminals via a plurality of antennas and decoding the data transmitted from each of the mobile terminals using STTD decoding.
16. A method for facilitating cooperative uplink transmission comprising:
a) receiving from a servicing base station a common resource to use for uplink transmission, the common resource also assigned to others of a group of mobile terminals;
b) receiving from the servicing base station a unique resource to use for the uplink transmission, a different unique resource being assigned to the other mobile terminals in the group of mobile terminals; and
c) transmitting information to the servicing base station using the common and unique resource wherein each of the mobile terminals in the group of mobile terminals concurrently uses the common resource and the different unique resource during the uplink transmission to provide a virtual multiple input multiple output uplink transmission.
17. The method of claim 16 wherein the common resource is an OFDM sub-carrier block in the time and frequency domain, such that the mobile terminals will concurrently transmit data in certain sub-carriers in the sub-carrier block.
18. The method of claim 17 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal assigned to at least one of the sub-carriers in the sub-carrier block, such that no two mobile terminals in the group of mobile terminals transmit the unique pilot information in a common sub-carrier.
19. The method of claim 17 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal, and further comprising creating the unique pilot signal in part from pilot information for at least one other mobile terminal in the group of mobile terminals and assigned to at least one of the sub-carriers in the sub-carrier block.
20. The method of claim 19 wherein the unique pilot signal is created using STTD coding from first pilot information and the pilot information for the at least one other mobile terminal in the group of mobile terminals.
21. The method of claim 16 wherein the common resource is at least one of a CDMA spreading code and a CDMA scrambling code, and further comprising spreading data to be transmitted by at least one of the CDMA spreading and CDMA scrambling codes.
22. The method of claim 21 wherein each unique resource is a unique code, and further comprising spreading or scrambling the data further with the unique code.
23. The method of claim 16 wherein the common resource is used for transmitting data and the unique resource is used for transmitting pilot information transmitted with the data.
24. The method of claim 16 further comprising receiving mobile terminal data from another mobile terminal in the group of mobile terminals wherein the information to be transmitted includes the mobile terminal data.
25. The method of claim 24 wherein the mobile terminal data and data is encoded using STTD encoding prior to being transmitted.
26. The method of claim 16 further comprising transmitting data to at least one of the mobile terminals in the group of mobile terminals.
27. The method of claim 26 wherein the data is transmitted to the at least one of the mobile terminals in the group of mobile terminals using communication resources other than those for the uplink or downlink transmission with the servicing base station.
28. The method of claim 26 wherein the data is transmitted to the at least one of the mobile terminals in the group of mobile terminals using communication resources used for the uplink or downlink transmission with the servicing base station.
29. The method of claim 28 wherein information to be transmitted to the servicing base station is transmitted during a first time period and the data is transmitted to the at least one of the mobile terminals during a second time period.
30. A base station for facilitating cooperative uplink transmission comprising transmit, receive, and control logic cooperatively adapted to:
a) identify a group of mobile terminals to provide cooperative uplink transmission;
b) assign a common resource via downlink transmissions to each of the mobile terminals in the group of mobile terminals, such that the common resource for each mobile terminal is the same and used for uplink transmission; and
c) assign a different unique resource via downlink transmissions to each mobile terminal, such that the unique resource for each of the mobile terminals is different and used for the uplink transmission, wherein each of the mobile terminals in the group of mobile terminals concurrently uses the common resource and a corresponding unique resource during the uplink transmission to provide a virtual multiple input multiple output uplink transmission.
31. The base station of claim 30 wherein the common resource is an OFDM sub-carrier block in the time and frequency domain, such that the mobile terminals will concurrently transmit data in certain sub-carriers in the sub-carrier block.
32. The base station of claim 31 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal assigned to at least one of the sub-carriers in the sub-carrier block, such that no two mobile terminals in the group of mobile terminals transmit the unique pilot information in a common sub-carrier.
33. The base station of claim 31 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal, which is created in part from pilot information for at least one other mobile terminal in the group of mobile terminals and assigned to at least one of the sub-carriers in the sub-carrier block.
34. The base station of claim 33 wherein the unique pilot signal for each mobile terminal is created using STTD coding from pilot information for a corresponding mobile terminal and the pilot information for the at least one other mobile terminal in the group of mobile terminals.
35. The base station of claim 30 wherein the common resource is at least one of a CDMA spreading code and a CDMA scrambling code, such that the mobile terminals will concurrently transmit data spread by at least one of the CDMA spreading and CDMA scrambling codes.
36. The base station of claim 35 wherein each unique resource is a unique code, such that the mobile terminals will concurrently transmit data further spread or scrambled by the unique code.
37. The base station of claim 30 wherein the receive, transmit, and control logic are further adapted to concurrently receive the uplink transmission from each of the mobile terminals in the group of mobile terminals via a plurality of antennas.
38. The base station of claim 30 wherein at least one of the mobile terminals in the group of mobile terminals has a plurality of antennas, and a plurality of unique resources are assigned to the at least one mobile terminal having the plurality of antennas.
39. The base station of claim 30 wherein the common resource is used for transmitting data and the unique resources are used for transmitting pilot information.
40. The base station of claim 30 wherein data transmitted from each of the mobile terminals includes data corresponding to the mobile terminal transmitting the data.
41. The base station of claim 40 wherein the receive, transmit, and control logic are further adapted to receive the uplink transmission from the mobile terminals via a plurality of antennas and decode the data transmitted from each of the mobile terminals using parallel decoding.
42. The base station of claim 30 wherein data in the uplink transmission for a mobile terminal in the group of mobile terminals includes data from another mobile terminal in the group of mobile terminals.
43. The base station of claim 42 wherein the data is encoded using STTD encoding.
44. The base station of claim 43 wherein the receive, transmit, and control logic are further adapted to receive the uplink transmission from the mobile terminals via a plurality of antennas and decoding the data transmitted from each of the mobile terminals using STTD decoding.
45. A mobile terminal for facilitating cooperative uplink transmission comprising receive, transmit, and control logic adapted to:
a) receive from a servicing base station a common resource to use for uplink transmission, the common resource also assigned to others mobile terminals in a group of mobile terminals;
b) receive from the servicing base station a unique resource to use for the uplink transmission, a different unique resource being assigned to the each mobile terminal; and
c) transmit information to the servicing base station using the common and unique resources wherein each of the mobile terminals in the group of mobile terminals concurrently uses the common resource and the different unique resource during the uplink transmission to provide a virtual multiple input multiple output uplink transmission.
46. The mobile terminal of claim 45 wherein the common resource is an OFDM sub-carrier block in the time and frequency domain, such that the mobile terminals will concurrently transmit data in certain sub-carriers in the sub-carrier block.
47. The mobile terminal of claim 46 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal assigned to at least one of the sub-carriers in the sub-carrier block, such that no two mobile terminals in the group of mobile terminals transmit the unique pilot information in a common sub-carrier.
48. The mobile terminal of claim 46 wherein each unique resource for each mobile terminal includes a sub-carrier for a unique pilot signal, and wherein the receive, transmit, and control logic are further adapted to create the unique pilot signal in part from pilot information for at least one other mobile terminal in the group of mobile terminals and assigned to at least one of the sub-carriers in the sub-carrier block.
49. The mobile terminal of claim 48 wherein the unique pilot signal is created using STTD coding from first pilot information and the pilot information for the at least one other mobile terminal in the group of mobile terminals.
50. The mobile terminal of claim 45 wherein the common resource is at least one of a CDMA spreading code and a CDMA scrambling code, and wherein the receive, transmit, and control logic are further adapted to spread data to be transmitted by at least one of the CDMA spreading and CDMA scrambling codes.
51. The mobile terminal of claim 50 wherein each unique resource is a unique code, and wherein the receive, transmit, and control logic are further adapted to spread or scramble the data further with the unique code.
52. The mobile terminal of claim 45 wherein the common resource is used for transmitting data and the unique resource is used for transmitting pilot information transmitted with the data.
53. The mobile terminal of claim 45 wherein the receive, transmit, and control logic are further adapted to receive mobile terminal data from another mobile terminal in the group of mobile terminals, and the information to be transmitted includes the mobile terminal data.
54. The mobile terminal of claim 53 wherein the mobile terminal data and data is encoded using STTD encoding prior to being transmitted.
55. The mobile terminal of claim 45 wherein the receive, transmit, and control logic are further adapted to transmit data to at least one of the mobile terminals in the group of mobile terminals.
56. The mobile terminal of claim 45 wherein the data is transmitted to the at least one of the mobile terminals in the group of mobile terminals using communication resources other than those for the uplink or downlink transmission with the servicing base station.
57. The mobile terminal of claim 45 wherein the data is transmitted to the at least one of the mobile terminals in the group of mobile terminals using communication resources used for the uplink or downlink transmission with the servicing base station.
58. The mobile terminal of claim 57 wherein information to be transmitted to the servicing base station is transmitted during a first time period and the data is transmitted to the at least one of the mobile terminals during a second time period.