Mobile device assisted coordinated multipoint transmission and reception
Idle mobile devices are used as cooperating devices to support coordinated multipoint transmission and reception for uplink and downlink communications between a primary mobile device and its serving base station. For uplink communications, the cooperating mobile devices receive the uplink transmission from the primary mobile device and retransmit the received data signal to the serving base station for the primary mobile device. For downlink communications, the cooperating mobile devices receive the downlink transmission from the serving base station and retransmit the received data signal to the primary mobile device.
1. A method implemented by a serving base station in a wireless communication network for supporting coordinated multipoint transmission and reception for a primary mobile device, comprising:
receiving, by the serving base station, during one iteration of a hybrid automatic repeat request (HARQ) process, a first data signal transmitted by a primary mobile device;
in response to an acknowledgement signal transmitted by the serving base station to the primary mobile device, receiving, by the serving base station, during a subsequent iteration of the HARQ process and in a subframe following a subframe that the first data signal is received, a second data signal as retransmitted by a cooperating mobile device in a coordinating set for the primary mobile device, wherein the second data signal includes a retransmission of the first data signal; and
combining the first and second data signals to produce a combined data signal.
2. The method of claim 1 , further comprising:
receiving link quality measurements from one or more candidate mobile devices including the cooperating mobile device;
computing a utility metric for each of the candidate mobile devices based on the link quality measurements; and
selecting the one or more candidate mobile devices, including the cooperating mobile device, for inclusion in the coordinating set for the primary mobile device.
3. The method of claim 2 , further comprising:
exchanging received link quality measurements with one or more cooperating base stations.
4. The method of claim 1 , further comprising:
adapting a modulation and coding scheme for the primary mobile device based on a probability of decoding the combined data signal.
5. The method of claim 1 , wherein the coordinating set includes at least one cooperating base station in the wireless communication network.
6. The method of claim 5 , wherein said receiving the second data signal is in cooperation with the first data signal being transmitted or received by the at least one cooperating base station.
7. The method of claim 1 , wherein the first data signal transmitted by the serving base station and the second data signal transmitted by the cooperating mobile device use a single radio access technology (RAT).
8. A base station in a wireless communication network for supporting coordinated multipoint transmission and reception for a primary mobile device, comprising:
a transceiver circuit configured to transmit and receive signals over a wireless communication channel; and
a processing circuit including a coordinated multipoint control circuit and configured to:
receive, during one iteration of a hybrid automatic repeat request (HARQ) process, a first data signal transmitted by a primary mobile device;
receive, during a subsequent iteration of the HARQ process and in a subframe following a subframe that the first data signal is received, a second data signal as retransmitted by a cooperating mobile device in a coordinating set for the primary mobile device responsive to an acknowledgement signal transmitted by the serving base station to the primary mobile device; and
combine the first and second data signals to produce a combined data signal.
9. The base station of claim 8 , wherein the processing circuit is further configured to:
receive link quality measurements from one or more candidate mobile devices including the cooperating mobile device;
compute a utility metric for each of the candidate mobile devices based on the link quality measurements; and
select the one or more candidate mobile devices, including the cooperating mobile device, for inclusion in the coordinating set for the primary mobile device.
10. The base station of claim 9 , wherein the processing circuit is further configured to exchange link quality measurements with one or more cooperating base stations.
11. The base station of claim 8 , wherein the processing circuit is further configured to adapt a modulation and coding scheme for the primary mobile device based on a probability of decoding the combined data signal.