Apparatus and associated method, by which to transmit beacon signals in a radio communication system

• US 6,717,926 B1
• Filed: 09/13/1999
• Issued: 04/06/2004
• Est. Priority Date: 09/13/1999
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Tobita, Hiroshi, Deboille, Mickael
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): LE, DANH C
• Application Number:
  US09/394,331
• Time in Patent Office: 1,667 Days
• Field of Search: 370/328, 370/338, 370/346, 370/450, 370/321, 370/324, 370/326, 370/337, 370/345, 370/347, 370/330, 455/422, 455/67.4, 455/63, 455/517, 375/146
• US Class Current: 370/330
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Apparatus, and associated method, by which to generate the beacon signals broadcast by network infrastructure of a radio communication system to mobile stations operable therein. The beacon signals are broadcast at selectable data rates, thereby to be of time durations corresponding to their respective data rates. When implemented in a multi-user, multi-rate communication scheme, communications which are effectuable at higher data rates are performed prior to communications effectuable at only lowered data rates. The beacon signals are transmitted at data rates corresponding to data rates at which communications are effectuated thereabout.

Claims

1. In a radio communication system having a network infrastructure with which a first mobile station and at least a second mobile station communicate data, the data to be communicated between the network infrastructure and the first mobile station selected to be communicated at a first communication-data data rate and the data to be communicated between the network infrastructure and the second mobile station selected to be communicated at a second communication-data data rate, wherein the communications occur in either a random-access period during which any mobile station may transmit, or in a polled-access period in which only polled mobile stations may transmit, an improvement of apparatus for facilitating communication of the data, said apparatus comprising:

a beacon signal generator coupled to receive indications of the first communication-data data rate and the second communication-data data rate, said beacon signal generator for generating a first beacon signal and at least a second beacon signal within a selected time during the polled-access period;

wherein the first beacon signal generated at a beacon-signal data rate at least as low as a lowest of the first communication-data data rate and the second communication-data data rate such that the first beacon signal is detectable by each of the mobile stations for which the beacon signal generator has received data-rate indications;

and wherein the second beacon signal generated at a rate corresponding to a highest of the first communication-data data rate and the at least second communication-data data rate.

2. The apparatus of claim 1 wherein the radio communication system defines a lowest acceptable data rate and wherein the first beacon signal generated by said beacon signal generator is generated at the lowest acceptable data rate.

3. The apparatus of claim 1 wherein the radio communication system defines a beacon interval, wherein said beacon signal generator generates a beacon signal at each successive beacon interval, the first beacon signal generated at a start of a first beacon interval and the second beacon signal generated at an end of the first beacon interval.

4. The apparatus of claim 1 wherein each of the first and at least second mobile stations, respectively, provide the network infrastructure with an indication of communication-data data rates at which respective ones of the first and at least second mobile stations are operable and wherein said apparatus further comprises a data rate determiner and sorter coupled to receive the indications, said data rate determiner and sorter for determining the first and at least second communication-data data rates at which each of the first and at least second mobile stations are operable and for sorting each of the mobile stations according to communication-data data rate operability associated therewith.

5. The apparatus of claim 4 wherein beacon signals generated by said beacon signal generator are generated at successive beacon intervals and wherein beacon signals subsequent to the first beacon signal are generated at the beacon intervals at beacon-signal data rates corresponding to the communication-data data rates sorted by said data rate determiner and sorter for communication subsequent to each subsequent beacon signal.

6. The apparatus of claim 5 wherein the first communication-data data rate is higher than the second communication-data data rate, wherein said data rate determiner and sorter selects communications effectuable at the first communication-data data rate to be effectuated prior to effectuation of communications effectuable at the second communication-data data rate.

7. The apparatus of claim 5 wherein said data rate determiner and sorter selects a communication sequence of communication of the data between the network infrastructure and the first mobile station and between the network infrastructure and the at least the second mobile station, the communication sequence to commence with data to be communicated with a mobile station operable at a highest of the first and at least second communication-data data rates.

8. The apparatus of claim 1 wherein data is communicated with the first and at least second mobile station at the first communication-data data rate, at the second communication-data data rate, and at least a third communication-data data rate and wherein said beacon signal generator is further operable to generate a third beacon signal, the third beacon signal generated at a beacon-signal data rate corresponding to a next-to highest of the first communication-data data rate, the second communication-data data rate, and the third communication-rate.

9. The apparatus of claim 1 wherein a frame structure is defined in the radio communication system and wherein the selected period within which said beacon signal generator generates the first beacon signal and the at least the second beacon signal comprises a frame of the frame structure.

10. The apparatus of claim 1 wherein the polled-access period is a contention free period according to IEEE 802.11 and wherein the beacon signals generated by said beacon signal generator are generated during the contention free period.

11. The apparatus of claim 1 wherein the network infrastructure includes an access point and wherein said beacon signal generator forms a portion of the access point.

12. The apparatus of claim 11 wherein the access point further comprises a point coordinator function and wherein said beacon signal generator is operable pursuant to the point coordinator function.

13. In a method for communicating in a radio communication system having network infrastructure with which a first mobile station and at least a second mobile station communicates data at a rate at least as fast as a lowest-allowable system data rate, the data to be communicated between the network infrastructure and the first mobile station selected to be communicated at a first communication-data data rate and the data to be communicated between the network infrastructure and the second mobile station selected to be communicated at a second communication-data data rate, wherein the communications occur in either a random-access period during which any mobile station may transmit, or in a polled-access period in which only polled mobile stations may transmit, an improvement of a method for facilitating communication of the data, said method comprising:

generating, within a selected time during the polled-access period, a first beacon signal at a beacon-signal data rate corresponding to the lowest-allowable system data rate;

determining, responsive to responses to the first beacon signal, communication-data data rates at which data is selected to be communicated between the network infrastructure and each of the first and at least second mobile stations, respectively; and

generating, within the selected time period, a second beacon signal at a beacon-signal data rate corresponding to a highest of the first communication-data data rate and the at least second communication-data data rate.

14. The method of claim 13 wherein the radio communication system defines a lowest acceptable data rate and wherein the beacon-signal data rate of the first beacon signal generated during said operation of generating the first beacon signal is generated at the lowest acceptable data rate.

15. The method of claim 13 wherein the radio communication system defines a beacon interval and wherein the first beacon signal generated during said operation of generating the first beacon signal is generated at a start of a first beacon interval.

16. The method of claim 15 wherein the second beacon signal generated during said operation of generating the second beacon signal is generated at an end of the first beacon interval.

17. The method of claim 13 wherein the network infrastructure includes an access point and wherein said operations of generating the first beacon signal and of generating the second beacon signal are performed at the access point.

18. The method of claim 13 comprising the additional operation, subsequent to said operation of generating the second beacon signal, of communicating data with at least a selected one of the first and at least second mobile stations, respectively, the at least selected one of the first and second mobile stations operable at the highest of the first communication-data data rate and the at least second communication-data data rate.

19. The method of claim 18 further comprising the additional operation of generating a third beacon signal at a beacon-signal data rate corresponding to a next-to highest of the first communication-data data rate and the at least second communication-data data rate.

20. Apparatus for facilitating communication of data in a radio communication system having at least one mobile station operable to communicate with network infrastructure at a first data rate and at least one mobile station operable to communicate with the network infrastructure at a second data rate, wherein the communications occur in either a random-access period during which any mobile station may transmit, or in a polled-access period in which only polled mobile stations may transmit, said apparatus comprising:

a beacon signal generator coupled to receive indications of the first data rate and the second data rate at which communications are possible in the radio communication system, said beacon signal generator for generating a first beacon signal and at least a second beacon signal within a selected time during the polled-access period;

wherein the first beacon signal is generated at a beacon-signal data rate at least as low as a lowest of the first communication-data data rate and the second data rate;

and wherein the second beacon signal is generated at a beacon-signal data rate corresponding to a highest of the first data rate and the second communication-data data rate.