Methods and apparatus for multi-carrier communication systems with automatic repeat request (ARQ)
Hybrid ARQ is employed in a multi-carrier communication system for retransmission of erroneous packets by taking advantage of time/frequency/space diversity and by combining ARQ functions at physical layer and MAC layers, making the multi-carrier system more robust in a high packet-error environment.
1. A method for a transmitter in a communication system, the method comprising:
allocating first and second subchannels for signal transmissions to a receiver in the communication system, the subchannels containing Orthogonal Frequency Division Multiplexing (OFDM) subcarriers;
transmitting, at a first transmission time, a first data packet over the first subchannel and a second data packet over the second subchannel;
receiving a signal from the receiver indicating an error in the first data packet received by the receiver; and
transmitting, at a second transmission time, a redundancy version of the first data packet over the second subchannel and a third data packet originally scheduled for the second subchannel over the first subchannel, wherein the first subchannel and second subchannels have different spatial configurations.
2. The method of claim 1 , wherein the transmission over the first or second subchannel uses an adaptive modulation and coding scheme.
3. The method of claim 1 , wherein the transmission over the first or second subchannel uses a rate-matching scheme.
4. The method of claim 1 , wherein the redundancy version of the first data packet is a progressive parity packet of the first data packet.
5. The method of claim 1 , wherein the signal from the receiver indicating an error in the first data packet is a negative acknowledgement (NACK) from the receiver.
6. The method of claim 1 , further comprising receiving a channel quality indicator (CQI), channel measurements, or both from the receiver.
7. A method for a receiver in a communication system, the method comprising:
receiving resource allocation information of first and second subchannels from a transmitter in the communication system, the subchannels containing Orthogonal Frequency Division Multiplexing (OFDM) subcarriers;
receiving from the transmitter, at a first reception time, a first data packet over the first subchannel and a second data packet over the second subchannel;
transmitting a signal to the transmitter indicating an error in the received first data packet;
receiving from the transmitter, at a second reception time, a redundancy version of the first data packet over the second subchannel and a third data packet originally scheduled for the second subchannel over the first subchannel, wherein the first subchannel and second subchannels have different spatial configurations; and
combining the data received over the first subchannel at the first reception time and the data received over the second subchannel at the second reception time to recover the first data packet.
8. The method of claim 7 , wherein the reception of the data packets over the first or second subchannel are performed in accordance with an adaptive modulation and coding scheme.
9. The method of claim 7 , wherein the reception of the data packets over the first or second subchannel are performed in accordance with a rate-matching scheme.
10. The method of claim 7 , wherein the redundancy version of the first data packet is a progressive parity packet of the first data packet.
11. The method of claim 7 , wherein the signal to the transmitter indicating an error in the received first data packet is a negative acknowledgement (NACK).
12. The method of claim 7 , further comprising transmitting a channel quality indicator (CQI), channel measurements, or both to the transmitter.
13. A transmitter for a communication system, the transmitter comprising:
an apparatus configured to allocate first and second subchannels for signal transmissions, the subchannels containing Orthogonal Frequency Division Multiplexing (OFDM) subcarriers;
an apparatus configured to transmit, at a first transmission time, a first data packet over the first subchannel and a second data packet over the second subchannel;
an apparatus configured to receive a signal indicating an error in the first data packet received by a receiver; and
an apparatus configured to transmit, at a second transmission time, a redundancy version of the first data packet over the second subchannel and a third data packet originally scheduled for the second subchannel over the first subchannel, wherein the first subchannel and second subchannels have different spatial configurations.
14. A receiver for a communication system, the receiver comprising:
an apparatus configured to receive resource allocation information of first and second subchannels from a transmitter in the communication system, the subchannels containing Orthogonal Frequency Division Multiplexing (OFDM) subcarriers;
an apparatus configured to receive from the transmitter, at a first reception time, a first data packet over the first subchannel and a second data packet over the second subchannel;
an apparatus configured to transmit a signal to the transmitter indicating an error in the received first data packet;
an apparatus configured to receive, at a second reception time, a redundancy version of the first data packet over the second subchannel and a third data packet originally scheduled for the second subchannel over the first subchannel, wherein the first subchannel and second subchannels have different spatial configurations; and
an apparatus configured to combine the data received over the first subchannel at the first reception time and the data received over the second subchannel at the second reception time to recover the first data packet.