Method and apparatus for controlling an amount of information in retransmission data packets using hybrid automatic repeat request protocol
View Patent ↗The present invention relates to a method for transmitting data packets from a mobile terminal to a base station using a hybrid automatic repeat request protocol and soft combining of received data. Further, the present invention provides a base station and a mobile terminal both adapted to perform the respective method steps. Moreover, a communication system is provided which comprises at least one base station and at least one mobile terminal. The present invention also provides a computer-readable medium for storing instructions that, when executed on a processor, cause the processor to transmit data packets from a mobile terminal to a base station using a hybrid automatic repeat request protocol and soft combining of received data. In order to restrict the interference caused by retransmissions, the present invention suggests controlling the amount of information in the retransmissions and thus the transmission power required for their transmission by TFCS restriction.
1. A method for controlling a transport format for retransmissions of data packets transmitted on uplink from a transmission apparatus to a receiving apparatus via at least one uplink data channel using a synchronous hybrid automatic repeat request (HARQ) protocol, the method comprising:
transmitting an uplink data packet via the uplink data channel from the transmission apparatus to the receiving apparatus,
simultaneously receiving a first information element and a second information element from the receiving apparatus at the transmission apparatus, wherein the first information element is used for determination whether to perform a retransmission of the uplink data packet at the transmission apparatus, and the second information element indicates a transport format for the retransmission, and
transmitting the retransmission from the transmission apparatus to the receiving apparatus according to the transport format indicated in the second information element using a synchronous transmission timing based on the synchronous HARQ protocol in case of the retransmission.
2. The method according to claim 1 , wherein the first information element is an ACK/NACK feedback message.
3. The method according to claim 1 , wherein the second information element is a control message.
4. The method according to claim 3 , wherein the control message is a TFC (Transmission Format Combination) control message.
5. The method according to claim 3 , wherein the transport format in the control message indicates the retransmission's amount of information necessary for successfully decoding of the combined data packet.
6. The method according to according to claim 1 , further comprising transmitting said uplink data packet via a first uplink data channel from the transmission apparatus to the receiving apparatus, and transmitting said retransmission via a second uplink data channel from the transmission apparatus to the receiving apparatus.
7. The method according to claim 6 , wherein transmission time interval of the first uplink data channel is smaller than the transmission time interval of the second uplink data channel.
8. The method according to claim 1 , wherein the transmitted uplink data packet and its retransmission are transmitted via at least one dedicated uplink transport channel.
9. A transmission apparatus for controlling a transport format for retransmissions of data packets transmitted on uplink to a receiving apparatus via at least one uplink data channel using a synchronous hybrid automatic repeat request (HARQ) protocol, the transmission apparatus comprising:
a transmitter section that transmits an uplink data packet via the uplink data channel to the receiving apparatus,
a receiver section that simultaneously receives a first information element and a second information element from the receiving apparatus, wherein the first information element is used for determination whether to perform a retransmission of the uplink data packet at the transmission apparatus, and the second information element indicates a transport format for the retransmission, and
wherein the transmitter section is adapted to transmit the retransmission from the transmission apparatus to the receiving apparatus according to the transport format indicated in the second information element using a synchronous transmission timing based on the synchronous HARQ protocol in case of the retransmission.
10. The transmission apparatus according to claim 9 , wherein the first information element is an ACK/NACK feedback message.
11. The transmission apparatus according to claim 9 , wherein the second information element is a control message.
12. A method for controlling a transport format for retransmissions of data packets transmitted on uplink from a transmission apparatus to a receiving apparatus via at least one uplink data channel using a synchronous hybrid automatic repeat request (HARQ) protocol, the method comprising:
receiving an uplink data packet via the uplink data channel from the transmission apparatus at the receiving apparatus,
simultaneously transmitting a first information element and a second information element from the receiving apparatus to the transmission apparatus, wherein the first information element is used for determination whether to perform a retransmission of the uplink data packet at the transmission apparatus, and the second information element indicates a transport format for the retransmission, and
receiving the retransmission from the transmission apparatus at the receiving apparatus according to the transport format indicated in the second information element using a synchronous transmission timing based on the synchronous HARQ protocol in case of the retransmission.
13. The method according to claim 12 , wherein the first information element is an ACK/NACK feedback message.
14. The method according to claim 12 , wherein the second information element is a control message.
15. The method according claim 12 , further comprising soft combining the uplink data packet and its retransmission at the receiving apparatus to obtain a combined data packet.
16. The method according to claim 15 , further comprising decoding the combined data packet at the receiving apparatus.
17. The method according to claim 15 , further comprising determining the transport format for the retransmission at the receiving apparatus based on the reception quality of the uplink data packet or the combined data packet.
18. The method according to claim 16 , further comprising determining the transport format for the retransmission at the receiving apparatus based on the reception quality of the uplink data packet or the combined data packet.
19. A receiving apparatus for controlling a transport format for retransmissions of data packets transmitted on uplink from a transmission apparatus to a receiving apparatus via at least one uplink data channel using a synchronous hybrid automatic repeat request (HARQ) protocol, the method comprising:
a receiver section that receives an uplink data packet via the uplink data channel from the transmission apparatus at the receiving apparatus, and
a transmitter section that simultaneously transmits a first information element and a second information element from the receiving apparatus to the transmission apparatus, wherein the first information element is used for determination whether to perform a retransmission of the uplink data packet at the transmission apparatus, and the second information element indicates a transport format for the retransmission,
where the receiver section is adapted to receive the retransmission from the transmission apparatus at the receiving apparatus according to the transport format indicated in the second information element using a synchronous transmission timing based on the synchronous HARQ protocol in case of the retransmission.
20. The receiving apparatus according to claim 19 , wherein the first information element is an ACK/NACK feedback message.
21. The receiving apparatus according to claim 19 , wherein the second information element is a control message.
22. The receiving apparatus according claim 19 , further comprising a decoder section that performs soft combining the uplink data packet and its retransmission at to obtain a combined data packet and that decodes the combined data packet.