Network device and method thereof

1. A network device for joint decoding of received signals in a cellular wireless communication system comprising a plurality of spatially distributed base stations interconnected to said network device by at least one backhaul interface having a round-trip delay being larger than a transmission interval for a Hybrid Automatic Repeat Request (HARQ) cycle of a HARQ algorithm employed by the cellular wireless communication system, said network device comprising:

a memory storing instructions; and

a processor coupled to the memory to execute the instructions to:

receive a plurality of baseband signals (BBSs) corresponding to uplink signals received by said plurality of base stations in uplink radio links, said uplink signals being associated with a plurality of uplink transmissions (ULTs) from a user device, said plurality of uplink transmissions including a first uplink transmission (ULT) that occurred in a cycle of said HARQ algorithm and a second uplink transmission (ULT) that occurred in a cycle of said HARQ algorithm subsequent to the cycle in which said first uplink transmission occurred; and

decode said second uplink transmission (ULT) from said user device by combining said plurality of baseband signals (BBSs).

2. The network device according to claim 1 , wherein the cellular wireless communication system is adapted to provide more uplink radio links from said user device than downlink radio links to said user device during at least one of said plurality of uplink transmissions (ULTs).

3. The network device according to claim 1 , said processor further adapted to establish the uplink radio links after sharing at least one transmission signature for said user device.

4. The network device according to claim 1 , wherein said processor executes said instructions to:

combine said plurality of baseband signals using soft combining or selection combining.

5. The network device according to claim 1 , wherein said network device is a central network controller, or an integrated part thereof, and said instructions further comprising: send an Acknowledgement (ACK) or a Negative Acknowledgement (NACK) to said plurality of base stations based on a result of the decoding of said second uplink transmission (ULT).

6. The network device according to claim 1 , wherein said network device is a base station, or an integrated part thereof.

7. The network device according to claim 6 , wherein said base station is a serving base station for said user device.

8. The network device according to claim 6 , wherein said base station is a base station having a lowest computational load among said plurality of base stations.

9. The network device according to claim 6 , wherein said processor executes said instructions to:

send an ACK or a NACK to said user device based on a result of the decoding of said second uplink transmission (ULT).

10. The network device according to claim 7 , wherein said processor executes said instructions to:

combine baseband signals (BBSs) corresponding to uplink signals for previous n−1 HARQ transmissions and a baseband signal (BBS) corresponding to an uplink signal for n-th HARQ transmission associated with said serving base station from said user device.

11. The network device according to claim 1 , wherein said processor executes said instructions to:

combine baseband signals (BBSs) corresponding to uplink signals for first n HARQ transmissions from each of said plurality of base stations).

12. The network device according to claim 1 , wherein the HARQ algorithm is configured to send an ACK at n-th HARQ transmission of a HARQ process associated with said user device even if a decoded result from the n HARQ transmissions at individual base stations is unsuccessful.

13. The network device according to claim 1 , wherein said processor executes said instructions to:

receive at least one of said plurality of baseband signals (BBSs) over the backhaul interface.

14. The network device according to claim 1 , wherein said transmission interval is a time period between said second uplink transmission and a transmission of an ACK or a NACK to said user device.

15. A method for joint decoding of received signals in a cellular wireless communication system comprising a plurality of spatially distributed base stations interconnected to a network device by at least one backhaul interface having a round-trip delay being larger than a transmission interval for a HARQ cycle of a HARQ algorithm employed by the cellular wireless communication system, the method comprising:

receiving a plurality of baseband signals (BBSs) corresponding to uplink signals received by said plurality of base stations in uplink radio links, said uplink signals being associated with a plurality of uplink transmissions (ULTs) from a user device, said plurality of uplink transmissions including a first uplink transmission (ULT) that occurred in a cycle of said HARQ algorithm and a second uplink transmission (ULT) that occurred in a cycle of said HARQ algorithm subsequent to the cycle in which said first uplink transmission occurred; and

decoding said uplink transmission (ULT) from said user device by combining said plurality of baseband signals (BBSs).

16. A non-transitory computer-readable storage medium storing computer-readable instructions that, when executed by a computer, cause the computer to perform the method according to claim 15 .

17. A network device for joint decoding of received signals in a cellular wireless communication system comprising a plurality of spatially distributed base stations interconnected to said network device by at least one backhaul interface having a round-trip delay being larger than a transmission interval for a Hybrid Automatic Repeat Request (HARQ) cycle of a HARQ algorithm employed by the cellular wireless communication system, said network device comprising:

a memory storing instructions; and

a processor coupled to the memory to execute the instructions to:

receive a plurality of baseband signals (BBSs) corresponding to uplink signals received by said plurality of base stations in uplink radio links, said uplink signals being associated with an uplink transmission (ULT) from a user device; and

decode said uplink transmission (ULT) from said user device by combining baseband signals, among the plurality of baseband signals, that correspond to uplink signals for previous n−1 HARQ transmissions and a baseband signal, among the plurality of baseband signals, that corresponds to an uplink signal for n-th HARQ transmission associated with said serving base station from said user device.