Packet data transmission in a MIMO system
A packet data transmission system comprises primary stations (PS) having signal transmitting and receiving means and antennas (PA 1 to PA 4 ) for propagating downlink signals and receiving uplink signals and a plurality of secondary stations (SS) able to roam within the coverage areas of the primary stations. Each secondary station (SS 1 ) has signal transmitting and receiving means, a predetermined number of antennas (SA 1 to SA 4 ), and means for monitoring its radio environment. Information about the radio environment is relayed as an uplink signal to the respective primary station which modifies its mode of transmission of packet data signals. The secondary station in response to the modified mode of transmission of the downlink signals adapts its receiver resources to process the packet data signals and effect cancellation of any interference.
1. A method of operating packet data transmission between a primary station and a secondary station, the method comprising:
monitoring, by a secondary station, a radio environment;
sending, by the secondary station, radio environment information to the primary station, the radio environment information being indicative of characteristics of a channel transfer function between one or more interference sources and secondary station antennas; and
configuring, by the secondary station, receiver resources of the secondary station for processing received data and interference signals based on the radio environment information.
2. The method of claim 1 , further comprising transmitting, by the secondary station, a recommendation such that the primary station is enabled to adapt a mode of signal transmission to the secondary station, in accordance with the recommendation.
3. The method of claim 2 , wherein the recommendation comprises the number of antennas or a subset of antennas for the primary station to use when transmitting packet data to the secondary station.
4. The method of claim 2 , wherein the recommendation comprises a maximum desired number of receivable transmission antennas to be used by the primary station.
5. The method of claim 2 , wherein the recommendation comprises a transmission format to be used by the primary station.
6. The method of claim 1 , wherein the radio environment information further comprises antenna coefficients which enable the primary station to optimize at least one parameter of antennas of the secondary station.
7. The method of claim 1 , further comprising determining, by the secondary station, the resources to be used for receiving packet data and the resources to be used for interference cancellation, and wherein a number of interference sources which can be cancelled by a linear combination of antenna outputs is equal to a number of receiver antennas minus a number of signals to be received from the primary station.
8. The method of claim 1 , further comprising monitoring, by the secondary station, a transfer function of paths between antennas of the primary station and the secondary station.
9. The method of claim 1 wherein the level of interference between the pairs of antennas includes interference in channels between pairs of interfering transmitter and receiver antennas.
10. The method of claim 1 , wherein the configuring is based on interference cancellation information derived from said characteristics of the channel transfer function.
11. A secondary station configured to be utilized in a packet data transmission system, the secondary station comprising:
a plurality of antennas; and
a processor coupled to the plurality of antennas, the processor being configured to:
monitor a radio environment of the packet data transmission system;
transmit a signal including radio environment information to a primary station, the radio environment information being indicative of characteristics of a channel transfer function between one or more interference sources and the secondary station antennas; and
adapt receiver resources of the secondary station for processing received data and interference signals based on the radio environment information.
12. The secondary station of claim 11 , wherein the processor is configured to transmit, via one or more of the plurality of antennas, a recommendation such that the primary station is enabled to adapt a mode of signal transmission to the secondary station in accordance with the recommendation.
13. The secondary station of claim 12 , wherein the recommendation comprises the number of antennas or a subset of antennas for the primary station to use when transmitting packet data to the secondary station.
14. The secondary station of claim 12 , wherein the recommendation comprises a maximum desired number of receivable transmission antennas to be used by the primary station.
15. The secondary station of claim 12 , wherein the recommendation comprises a transmission format to be used by the primary station.
16. The secondary station of claim 11 , wherein the radio environment information further includes antenna coefficients which enable the primary station to optimize at least one parameter of the antennas of the secondary station.
17. The secondary station of claim 11 , wherein the processor is configured to determine resources to be used for receiving packet data and resources to be used for interference cancellation, and wherein a number of interference sources which can be cancelled by a linear combination of antenna outputs is equal to a number of receiver antennas minus a number of signals to be received from the primary station.
18. The secondary station of claim 11 , wherein the processor is configured to allocate resources for processing the received data and interference by choosing, based on characteristics of the channel transfer functions between interference sources and the plurality of antennas, selected ones of the plurality of antennas for receiving interference signals for interference cancellation.
19. The secondary station of claim 11 , wherein the adaptation is based on interference cancellation information derived from said characteristics of the channel transfer function.
20. A primary station configured to be utilized in a packet data transmission system, the primary station comprising:
a plurality of antennas; and
a processor coupled to the plurality of antennas, the processor being configured to:
receive a signal including radio environment information from a secondary station, the radio environment information being indicative of characteristics of a channel transfer function between one or more interference sources and secondary station antennas; and
allocate, based on the radio environment information, transmission resources of the plurality of antennas for transmission of communication signals to the secondary station such that the secondary station is enabled to process received data and interference signals based on the radio environment information.
21. The primary station of claim 20 , wherein the processor is configured to receive a recommendation from the secondary station, and wherein the processor is configured to adapt a mode of signal transmission to the secondary station based on the recommendation.
22. The primary station of claim 21 , wherein the recommendation comprises the number of antennas or a subset of antennas for the primary station to use when transmitting packet data to the secondary station.
23. The primary station of claim 21 , wherein the recommendation comprises a maximum desired number of receivable transmission antennas to be used by the primary station.
24. The primary station of claim 21 , wherein the recommendation comprises a transmission format to be used by the primary station.
25. The primary station of claim 20 , wherein radio environment information further includes antenna coefficients, and wherein the processor is configured to optimize at least one parameter of antennas of the secondary station based on the antenna coefficients.
26. The primary station of claim 20 , wherein the allocation is based on interference cancellation information derived from said characteristics of the channel transfer function.