Wireless Communication Systems

• US 20090061887A1
• Filed: 05/22/2008
• Published: 03/05/2009
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Power, Kevin, Hart, Michael John Beems, Zhou, Yuefeng
• Granted Patent: US 8,355,370 B2
• Time in Patent Office: Days
• US Class Current: 455/450
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

A wireless communication method used in a system comprising a base station and a plurality of fixed or mobile subscriber stations, the base station maintaining connections with each of the subscriber stations by performing wireless communication in units of frames, and within each frame, allocating resources for data transmissions and signalling in the wireless communication system. The method involves providing, in each frame, a new dedicated shared channel for use by the subscriber stations to report a connection quality to the base station. To save bandwidth in the system, the resources allocated to the shared channel are less than the total resources needed for every subscriber station to report individually within the same frame. The method includes, in the base station, allocating resources to the shared channel, dividing the shared channel into a plurality of reporting opportunities, and transmitting requests for reports to the subscriber stations; and in the subscriber stations, responding to said requests by randomly selecting one of said reporting opportunities and sending a report on the channel quality. Preferably, the responding step is conditional upon the channel quality experienced by each subscriber station meeting a threshold condition set by the base station and included in the requests.

Claims

1. A wireless communication system comprising a base station and a plurality of fixed or mobile subscriber stations, the base station maintaining connections with each of the subscriber stations by performing wireless communication in units of frames, and within each frame, allocating resources for data transmissions and signalling in the wireless communication system, wherein:

each frame includes a shared channel provided for the subscriber stations to report a connection quality to the base station, the resources allocated to the shared channel being less than the total resources needed for every subscriber station to report.

2. The wireless communication system according to claim 1, wherein each frame includes a downlink subframe for transmissions from the base station to the subscriber stations, and an uplink subframe for transmissions from the subscriber stations to the base station, and wherein the shared channel is included in the uplink subframe.

3. The wireless communication system according to claim 2, wherein each report includes information about the transmission quality in the immediately-preceding downlink subframe.

4. The wireless communication system according to claim 3, wherein said information is an indication of whether a threshold condition has been met, and the base station is arranged to communicate the threshold condition to the subscriber stations by the base station within the downlink subframe.

5. The wireless communication system according to claim 4, wherein the base station is arranged to communicate different threshold conditions to different subscriber stations or sets of subscriber stations.

6. The wireless communication system according to claim 2, wherein the information in each said report includes a value representing the transmission quality.

7. The wireless communication system according to claim 2, wherein each report includes a code identifying the subscriber station to the base station.

8. The wireless communication system according to claim 7, wherein the shared channel is divided into a number of reporting opportunities less than the number of subscriber stations, and each reporting opportunity allows at least one subscriber station to report the connection quality to the base station.

9. The wireless communication system according to claim 8, wherein each reporting opportunity allows multiple subscriber stations to report to the base station which distinguishes the reports based on the codes.

10. The wireless communication system according to claim 2 wherein the shared channel is dynamically sized by the base station by altering the amount of resources allocated within the uplink subframe at least in the time dimension thereof.

11. A base station for use in a wireless communication system to provide connections to a plurality of subscriber stations and communicating with the subscriber stations in units of frames for data transmission and signalling, the base station comprising resource allocation means for allocating available resources in the system to fulfil data transmission requirements of the subscriber stations and signalling requirements, wherein the resource allocation means is arranged to allocate resources to a shared channel for use by the subscriber stations to send reports to the base station, the shared channel providing a number of reporting opportunities in each frame which is less than the number of subscriber stations.

12. The base station according to claim 11, wherein the base station is further arranged to solicit said reports by sending requests to the subscriber stations.

13. The base station according to claim 12, wherein said reports include reports on connection quality between the base station and the subscriber stations.

14. The base station according to claim 11 wherein the base station is responsive to the reports received from the subscriber stations to adjust modulation and coding parameters used in a succeeding frame.

15. A subscriber station, for use in a wireless communication system in which a base station communicates with a plurality of subscriber stations and provides a shared channel for use by the subscriber stations to send reports to the base station, the subscriber station being configured to:

receive a threshold from the base station, the threshold representing a minimum acceptable level of communication quality;

monitor a communication quality with the base station and generate a report when the communication quality crosses the threshold; and

transmit the report to the base station on the shared channel.

16. A frame format used in a wireless communication system comprising:

a downlink subframe for containing downlink data and signalling information to be transmitted from a base station, to subscriber stations of the wireless communication system having a connection to the base station; and

an uplink subframe for containing uplink data and signalling information to be transmitted from the subscriber stations to the base station;

wherein

the uplink subframe includes a shared channel provided for the subscriber stations to report a connection quality to the base station, the resources allocated to the shared channel being less than the total resources needed for every subscriber station to report to the base station.

17. A wireless communication method used in a system comprising a base station and a plurality of fixed or mobile subscriber stations, the base station maintaining connections with each of the subscriber stations by performing wireless communication in units of frames, and within each frame, allocating resources for data transmissions and signalling in the wireless communication system, wherein the method comprises:

providing, in each frame, a shared channel for the subscriber stations to report a connection quality to the base station, the resources allocated to the shared channel being less than the total resources needed for every subscriber station to report.

18. A computer-readable medium having stored thereon software which, when executed by a processor of a base station and subscriber stations in a wireless communication system, carries out the method of claim 17.