Coordinated multipoint (COMP) techniques for reducing downlink interference from uplink signals
Base stations (BSs) can remove inter-BS interference components from received uplink signals using downlink information communicated over a backhaul network. The downlink information is associated with downlink transmissions of neighboring base stations, and is used to remove the inter-BS interference in accordance with interference cancellation techniques, e.g., signal interference cancellation (SIC), etc. The downlink information includes information associated with downlink transmission of the interfering BSs, such as information bits (e.g., data), parity information, control information, modulation and coding scheme (MCS) parameters, forward error correction (FEC) parameters, and other information. Additionally, inter-BS interference can be suppressed using channel information of interference channels using interference suppression techniques, e.g., interference rejection combining (IRC), etc.
1. A method for removing interference from received signals, the method comprising:
transmitting, by a base station, a serving downlink transmission to a mobile device, the base station and the mobile device engaging in full-duplexed communications such that uplink and downlink signals are simultaneously communicated over the same frequencies;
receiving, by a base station, an uplink signal comprising an uplink transmission from a mobile device and interference attributable to the serving downlink transmission and neighboring downlink transmissions of one or more neighboring base stations, wherein the uplink transmission, the serving downlink transmission, and the neighboring downlink transmissions are communicated over common radio resources;
receiving, by the base station, downlink information from the one or more neighboring base stations over a backhaul network, the downlink information corresponding to the neighboring downlink transmissions of the one or more neighboring base stations; and
removing at least some of the interference from the uplink signal in accordance with both the downlink information corresponding to the neighboring downlink transmissions and the serving downlink transmission.
2. The method of claim 1 , wherein the downlink information comprises data streams carried by the neighboring downlink transmissions of the one or more neighboring base stations.
3. The method of claim 1 , wherein the downlink information includes information bits and parity bits of data streams carried by the neighboring downlink transmissions.
4. The method of claim 1 , wherein the downlink information comprises information bits of the neighboring downlink transmissions of the one or more neighboring base stations, the downlink information excluding parity bits of the neighboring downlink transmissions of the one or more neighboring base stations.
5. The method of claim 4 , wherein the downlink information further comprises modulation and coding scheme (MCS) parameters and forward error correction (FEC) parameters of the neighboring downlink transmissions of the one or more neighboring base stations.
6. The method of claim 5 , further comprising:
reconstructing the neighboring downlink transmissions in accordance with the information bits, the MCS parameters, and the FEC parameters communicated over the backhaul network; and
performing signal interference cancellation on the received uplink transmission in accordance with the reconstructed neighboring downlink transmissions.
7. The method of claim 1 , wherein the downlink information comprises interference signals associated with the neighboring downlink transmissions, the interference signals being computed by the one or more neighboring base stations.
8. The method of claim 1 , wherein removing interference from the received uplink transmission in accordance with the downlink information and the serving downlink transmission includes:
identifying interference channels extending between the base station and the one or more neighboring base stations;
reconstructing the neighboring downlink transmissions in accordance with the downlink information;
computing neighboring interference components in accordance with the reconstructed neighboring downlink transmissions and the interference channels; and
subtracting the neighboring interference components from the received uplink transmission.
9. The method of claim 8 , wherein subtracting the interference components from the received uplink transmission comprises:
subtracting the interference components from the received uplink transmission in the digital domain.
10. The method of claim 8 , wherein subtracting the interference components from the received uplink transmission comprises:
subtracting the interference components from the received uplink transmission in the analog domain.
11. A base station comprising:
a processor; and
a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to:
transmit a serving downlink transmission to a mobile device, the base station and the mobile device engaging in full-duplexed communications such that uplink and downlink signals are simultaneously communicated over the same frequencies;
receive an uplink signal comprising an uplink transmission from a mobile device and interference attributable to the serving downlink transmission and neighboring downlink transmissions of one or more neighboring base stations, wherein the uplink transmission, the serving downlink transmission, and the neighboring downlink transmissions are communicated over common radio resources;
receive downlink information from the one or more neighboring base stations over a backhaul network, the downlink information corresponding to the neighboring downlink transmissions of the one or more neighboring base stations; and
remove at least some of the interference from the uplink signal in accordance with both the downlink information corresponding to the neighboring downlink transmissions and the serving downlink transmission.
12. The base station of claim 11 , wherein the downlink information comprises data streams carried by the neighboring downlink transmissions of the one or more neighboring base stations.
13. The base station of claim 11 , wherein the downlink information includes information bits and parity bits of data streams carried by the neighboring downlink transmissions.
14. The base station of claim 11 , wherein the downlink information comprises information bits of the neighboring downlink transmissions of the one or more neighboring base stations, but excludes parity bits of the neighboring downlink transmissions of the one or more neighboring base stations.
15. The base station of claim 14 , wherein the downlink information further comprises modulation and coding scheme (MCS) parameters and forward error correction (FEC) parameters of the neighboring downlink transmissions of the one or more neighboring base stations.
16. The base station of claim 11 , wherein the downlink information comprise interference signals associated with the neighboring downlink transmissions, the interference signals being computed by the one or more neighboring base stations.
17. The base station of claim 11 , wherein the instructions to remove at least some of the interference from the uplink signal in accordance with both the downlink information corresponding to the neighboring downlink transmissions and the serving downlink transmission include instructions to:
remove, from the uplink signal, interference corresponding to both the neighboring downlink transmissions and the serving downlink transmission.
18. The method of claim 1 , wherein removing at least some of the interference from the uplink signal in accordance with both the downlink information corresponding to the neighboring downlink transmissions and the serving downlink transmission comprises:
removing, from the uplink signal, interference corresponding to both the neighboring downlink transmissions and the serving downlink transmission.