Methods for supporting MIMO transmission in OFDM applications
Aspects of the present invention provide MAC enhancements to support the PHY features of a MIMO-OFDMA framework. The MAC enhancements involve DL burst assignment to support adaptive MIMO transmission, UL burst assignment to support adaptive MIMO transmission, fast feedback channel operation to support wireless terminal dynamic feedback of MIMO mode selection, for example space time transmit diversity (STTD) or spatial multiplexing (SM), and/or permutation mode selection, for example diversity or adjacent subcarrier mode, dynamic CQICH allocation and de-allocation and the use of CQICH_ID for DL burst allocation. One or more of these enhancements is included in a given implementation. Methods are also provided for implementing the MAC enhancements.
1. A method for enabling downlink transmission in a MIMO enabled OFDM system from a base station to at least one wireless terminal, the method comprising:
establishing a three dimensional frame, the three dimensional frame including:
a first dimension including a plurality of rows, at least one of the plurality of rows designated by a subchannel;
a second dimension including a plurality of columns, at least one of the plurality of columns designated by an OFDMA symbol;
a third dimension including a plurality of layers;
the base station transmitting to the at least one wireless terminal:
a location of a region within the three dimensional frame expressed by an OFDMA symbol offset, a subchannel offset, and at least one of the plurality of layers;
the base station transmitting to the at least one wireless terminal for each of the plurality of layers:
a transmission profile; and
an identifier for identifying a connection between the base station and the at least one wireless terminal.
2. The method of claim 1 , wherein the location of the region within the three dimensional frame is expressed by a number of OFDMA symbols the region occupies, and a number of subchannels the region occupies, the base station further transmitting to the at least one wireless terminal, for each region:
a diversity multiplexing format used for transmitting information located in the region of the data frame.
3. The method of claim 1 , wherein the transmission profile is a downlink interval usage code (DIUC).
4. The method according to claim 1 , wherein the diversity multiplexing format is defined by an indicator for indicating a predefined matrix transmission format.
5. The method of claim 1 , wherein the identifier is a connection identification (CID) for the connection between the base station and the at least one wireless terminal.
6. The method of claim 1 , wherein the identifier is a value uniquely allocated to a single wireless terminal for a limited duration of time.
7. The method of claim 6 , wherein the identifier is a channel quality identification channel (CQICH) identifier.
8. The method of claim 1 , wherein the transmissions are transmitted in a downlink information element of the three dimensional frame, the three dimensional frame transmitted from the base station to the at least one wireless terminal.
9. The method of claim 1 , wherein the transmissions are transmitted in accordance with a downlink information element of the three dimensional frame, the downlink information element comprising a data field for each respective transmission by the base station.
10. The method of claim 9 , wherein each data field is occupied by one or more bits.
11. The method of claim 8 , the downlink information element comprising the following format:
Syntax
Size
Notes
MIMO DL Basic IE ( ) {
Extended DIUC
4 bits
0x05
Length
8 bits
Length in bytes
Num Region
4 bits
for ( i = 0; i< Num Region; i++) {
OFDMA Symbol offset
10 bits
Subchannel offset
5 bits
Boosting
3 bits
No. OFDMA Symbols
9 bits
No. subchannels
5 bits
Matrix indicator
3 bits
STC matrix
000 = Matrix A
001 = Matrix B
010 = Matrix C
011 = Matrix D
100 = Matrix E
101-111 = Reserved
Num layer
2 bits
for (j = 0; j< Num layer; j++) {
if (INC CID == 1) {
CID
16 bits
}
Layer index
2 bits
DIUC
4 bits
0-11 burst profiles
}
}.
12. The method of claim 8 , the downlink information element comprising the following format:
Syntax
Size
Notes
MIMO DL Enhanced IE ( ) {
Extended DIUC
4 bits
0x06
Length
8 bits
Length in bytes
Num_Region
4 bits
for ( i = 0; i< Num Region; i++) {
OFDMA Symbol offset
10 bits
Subchannel offset
5 bits
Boosting
3 bits
No. OFDMA Symbols
9 bits
No. subchannels
5 bits
Num_layer
2 bits
for (j = 0; j< Num layer; j++) {
if (INC CID == 1) {
CQICH ID
8 bits
}
Layer index
2 bits
DIUC
4 bits
0-11 burst profiles
}
}.
13. A method for enabling uplink transmission in a MIMO enabled OFDM system from at least one wireless terminal to a base station, the method comprising:
establishing a three dimensional frame, the three dimensional frame including:
a first dimension including a plurality of rows, at least one of the plurality of rows designated by a subchannel;
a second dimension including a plurality of columns, at least one of the plurality of columns designated by an OFDMA symbol;
a third dimension including a plurality of layers;
the at least one wireless terminal receiving from the base station a location of a region within the three dimensional frame expressed by an OFDMA symbol offset, a subchannel offset, and at least one of the plurality of layers;
the at least one wireless terminal receiving from the base station for each of the plurality of layers:
a transmission profile and an identifier for identifying a connection between the base station and the at least one wireless terminal.
14. The method of claim 13 , wherein the at least one wireless terminal further receiving from the base station for each of the plurality of layers a diversity multiplexing format used for transmitting the information located in the region, the diversity multiplexing format is defined by an indicator for indicating a predefined matrix transmission format when the at least one wireless terminal has at least two transmit antennas.
15. The method of claim 13 , wherein the diversity multiplexing format is defined by an indicator for indicating a first subcarrier pilot pattern of the at least one wireless terminal having a single transmit antenna, the at least one wireless terminal being used in combination with a second wireless terminal having a single transmit antenna and having a second subcarrier pilot pattern, the at least one wireless terminals and the second wireless terminal providing a collaborative spatial multiplexing diversity.
16. The method of claim 13 , wherein the transmissions are transmitted in an uplink information element of the three dimensional frame, the three dimensional frame transmitted from the base station to the at least one wireless terminal.
17. The method of claim 13 , wherein the transmissions are transmitted in accordance with an uplink information element of the three dimensional frame, the uplink information element comprised of a data field for each respective transmission by the base station.
18. The method of claim 17 , wherein each data field is occupied by one or more bits.
19. The method of claim 16 , the uplink information element comprising the following format:
Syntax
Size
Notes
MIMO UL Basic IE ( ) {
Extended UIUC
4 bits
0x02
Length
4 bits
Length in bytes
Num Assign
For (i=0; i< Num Assign; i++ )
{
CID
16 bits
SS basic CID
MIMO Control
1 bit
For dual transmission capable
SS
0: STTD; 1: SM
For Collaborative SM capable
SS
0: pilot pattern A; 1: pilot
pattern B
Duration
48 bits
In OFDMA slots
}
}.
20. The method of claim 1 , wherein a transmitter in the MIMO enabled OFDM communications system is adapted to perform the method of claim 1 .
21. The method of claim 13 , wherein the transmission profile is a uplink interval usage code (UIUC).
22. The method of claim 13 , wherein the identifier is a connection identification (CID) for the connection between the base station and the at least one wireless terminal.