Secondary station and method of operating the station
View Patent ↗A secondary station has a receiver capable of resolving signals received as a plurality of multipath signals from a plurality of base stations during a soft handover process. This capability may, for example, be provided by a Rake receiver. In order to decode and act upon the received signals in a very short period of time, signals arriving after a predetermined time are not processed by the receiver which is able instead to process weaker signals which arrived before the time. Such a secondary station is particularly suitable for decoding and acting upon power control commands included in received signals in a UMTS system, for which a very limited period of time is provided by the UMTS specification. The predetermined time may be the time after which signals are received too late for use in determining the next power control change.
1. A secondary station for use in a radio communication system comprising a plurality of primary stations, the secondary station comprising a processor configured to:
communicate simultaneously with at least two primary stations,
resolve transmitted signals from the at least two primary stations received by a receiver of the secondary station as a plurality of multipath signals, and
determine whether to allocate each multipath signal to the receiver based on whether its time of arrival occurs within a window of arrival.
2. The secondary station as claimed in claim 1 , wherein the receiver comprises a Rake receiver having a plurality of fingers.
3. The secondary station as claimed in claim 1 , wherein the processor is further configured to adjust power of uplink transmissions in response to power control commands received from the at least two primary stations, and the receiver is configured to resolve power control commands received via the plurality of multipath signals.
4. The secondary station as claimed in claim 3 , wherein the processor is further configured to:
adjust transmission power at predetermined times, and not allocate to the receiver late signals, having a time of arrival which is less than a predetermined interval before a next time for adjustment of the transmission power.
5. The secondary station as claimed in claim 4 , wherein at least some of the late signals are used in determining a subsequent power control adjustment.
6. A method of operating a secondary station comprising the acts of:
communicating simultaneously by the secondary station with at least two primary stations,
receiving transmitted signals from the at least two primary stations as a plurality of multipath signals,
processing the received multipath signals to resolve the transmitted signals, and
determining whether to process each multipath signal based on whether its time of arrival occurs within a window of arrival.
7. The method as claimed in claim 6 ,wherein the processing act is performed by a Rake receiver having a plurality of fingers.
8. The method as claimed in claim 6 , further comprising the acts of:
adjusting power of uplink transmissions in response to power control commands received from the at least two primary stations; and
resolving power control commands received via the plurality of multipath signals.
9. The method as claimed in claim 8 , further comprising the acts of:
adjusting transmission power at predetermined times; and
not processing late signals, having a time of arrival which is less than a predetermined interval before a next time for adjustment of the transmission power.
10. The method as claimed in claim 9 , further comprising the act of determining a subsequent power control adjustment using at least some of the late signals.
11. A system comprising:
a secondary station; and
at least two primary stations; wherein the secondary station comprises a processor configured to:
communicate simultaneously with the at least two primary stations;
resolve transmitted signals from the at least two primary stations received by a receiver of the secondary station as a plurality of multipath signals; and
determine whether to allocate each multipath signal to the receiver based on whether its time of arrival occurs within a window of arrival.
12. The system of claim 11 , wherein the receiver comprises a Rake receiver having a plurality of fingers.
13. The system of claim 11 , wherein the processor is further configured to adjust power of uplink transmissions in response to power control commands received from the at least two primary stations, and the receiver is configured to resolve power control commands received via the plurality of multipath signals.
14. The system of claim 13 , wherein the processor is further configured to:
adjust transmission power at predetermined times, and
not allocate to the receiver late signals having a late time of arrival which is less than a predetermined interval before a next time for adjustment of the transmission power.
15. The system of claim 14 , wherein at least some of the late signals are used in determining a subsequent power control adjustment.