Multiple user spread-spectrum communication system

• US 5,210,771 A
• Filed: 08/01/1991
• Issued: 05/11/1993
• Est. Priority Date: 08/01/1991
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Kotzin, Michael D., Schaeffer, Dennis R.
• Primary Examiner(s): CAIN, DAVID C
• Application Number:
  US07/739,037
• Time in Patent Office: 649 Days
• Field of Search: 375/1
• US Class Current: 375/132
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00
• CPC Class Codes: H04W 36/16 Performing reselection for specific purposes
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

A communication system having a site employing a plurality of communication channels. Each channel is assigned a desired received signal strength threshold. A channel is assigned to a subscriber unit based upon the strength of the signal received at the site and the power control range of the subscriber unit. The selection of a channel may be performed either by the site or the subscriber unit. In an FDMA environment, each separate frequency division channel may be assigned different received signal strength thresholds. In a non-overlapping time interval (TDMA) environment, each separate time division channel may be assigned different received signal strength thresholds. In another embodiment, a combination of FDMA and TDMA environments can be used.

Claims

1. A communication system comprising:

a site having a first communication channel associated therewith, said first communication channel having a first received signal strength threshold assigned thereto, and a second communication channel associated therewith, said second communication channel having a second received signal strength, different from said first received signal strength threshold, threshold assigned thereto, said first and second communication channels serving substantially a single coverage area; and

means for selecting one of said first and second communication channels for use by a subscriber unit.

2. The communication system of claim 1 wherein said subscriber unit comprises said means for selecting and wherein said selection is based upon a signal received from said site.

3. The communication system of claim 1 wherein said first and second communication channels are frequency division channels.

4. The communication system of claim 1 wherein said first and second communication channels are time division channels.

5. The communication system of claim 1 wherein said first and second communication channels are frequency and time division channels.

6. The communication system of claim 1 wherein said communication system is a spread spectrum communication system.

7. The communication system of claim 6 wherein said spread spectrum communication system is a direct sequence code division multiple access communication system.

8. The communication system of claim 6 wherein said spread spectrum communication system is a frequency hopping code division multiple access communication system.

9. A communication system comprising:

a site having a first communication channel associated therewith, said first communication channel having a first received signal strength threshold assigned thereto, and a second communication channel associated therewith, said second communication channel having a second received signal strength, different from said first received signal strength, threshold assigned thereto, said first and second communication channels serving substantially a single coverage area;

means for selecting one of said first and second communication channels for use by a subscriber unit; and

means for adjusting a transmitter power level of said subscriber unit to said received signal strength threshold of said selected communication channel.

10. The communication system of claim 9 wherein said subscriber unit comprises said means for selecting and wherein said selection is based upon a signal received from said site.

11. The communication system of claim 9 wherein said first and second communication channels are frequency division channels.

12. The communication system of claim 9 wherein said first and second communication channels are time division channels.

13. The communication system of claim 9 wherein said first and second communication channels are frequencies and time division channels.

14. The communication system of claim 9 wherein said communication system is a spread spectrum communication system.

15. The communication system of claim 14 wherein said spread spectrum communication system is a direct sequence code division multiple access communication system.

16. The communication system of claim 14 wherein said spread spectrum communication system is a frequency hopping code division multiple access communication system.

17. A method of assigning one of a plurality of communication channels assigned to a single site, each of said plurality of communication channels serving substantially a single coverage area, to a subscriber unit, said method comprising the steps of:

receiving an information signal at said subscriber unit from said single site, said information signal having information on a received signal strength threshold for each of said plurality of communication channels;

selecting one of said plurality of communication channels; and

setting a transmit power level of said subscriber unit such that a signal strength of a signal received at said site from said subscriber unit will match said received signal strength threshold for said selected channel.

18. The method of claim 17 wherein said step of selecting comprising the steps of:

measuring the strength of said information signal received at said subscriber unit;

determining a power power loss of said information signal between the transmission of said information signal from said site to said subscriber unit; and

selecting one of said plurality of communication channels based upon a matching of a dynamic power transmission range of said subscriber unit to said received signal strength threshold information for each of said plurality of communication channels.

19. The method of claim 18 wherein said step of determining comprises the steps of:

receiving a transmission power level information from said site; and

calculating the difference between said transmission power level information and said strength of said information signal received at said subscriber unit.

20. A method of assigning one of a plurality of communication channels assigned to a single site, each of said plurality of communication channels serving substantially a single coverage area, to a subscriber unit, said method comprising the steps of:

transmitting a request for access to a communication system from said subscriber unit to said single site;

measuring a signal strength of said request at said site;

determining a power loss of said request between the transmission of said request from said subscriber unit to said site;

selecting one of said plurality of communication channels based upon said signal strength of said request and a dynamic power transmission range of said subscriber unit; and

setting a transmit power level of said subscriber unit such that a signal strength of a signal received at said site from said subscriber unit will match said received signal strength threshold for said selected channel.

21. The method of claim 20 wherein said step of selecting comprises the step of determining a power loss of said information signal between the transmission of said information signal from said site to said subscriber unit.

22. The method of claim 21 wherein said step of determining comprises the steps of:

receiving a transmission power level information at said site from said subscriber unit; and

calculating the difference between said transmission power level information and said strength of said request received at said site.

23. The method of claim 21 wherein said step of determining comprises the step of calculating the difference between a standard transmission power level and said strength of said request received at said site.

24. A communication system comprising:

means for measuring a signal strength of a received signal; and

means for selecting a communication channel of a plurality of communication channels, each of said plurality of communication channels serving substantially a single coverage area, within a single site based upon said signal strength of said received signal.

25. The communication system of claim 24 further comprising means for sending said communication channel to a transmitter of said received signal.

26. The communication system of claim 24 wherein said means for measuring a power level comprises a base site.

27. The communication system of claim 24 wherein said communication channel is a time division channel.

28. The communication system of claim 24 wherein said communication system is a spread spectrum communication system.

29. The communication system of claim 28 wherein said spread spectrum communication system is a code division multiple access communication system.

30. The communication system of claim 24 wherein said communication channel is a frequency division channel.

31. The communication system of claim 24 wherein said communication channel is a radio communication signal.

32. The communication system of claim 24 wherein said communication channel is a frequency and a time division channel.

33. A communication system comprising:

means for sending a power level threshold signal for a plurality of communication channel segments, each of said plurality of communication channel segments serving substantially a single coverage area, from a single base site;

means for selecting one of said plurality of communication channel segments based upon said power level threshold signal received by a subscriber;

means for transmitting a first signal in an access channel of said selected one of said plurality of communication channel segments from said subscriber to said base site; and

means for selecting a communication channel within said selected one of said plurality of communication channel segments.

34. The communication system of claim 33 further comprising a means for sending said communication channel from said base site to said subscriber.

35. The communication system of claim 33 wherein each of said plurality of communication channel segments has associated therewith a received signal strength threshold.

36. The communication system of claim 35 wherein a first end communication channel segment of said plurality of communication channel segments has a first power level associated therewith, a second end communication channel segment of said plurality of communication channel segments has a second power level associated therewith, and a center communication segment of said plurality of communication channel segments disposed between said first and second ends of said plurality of communication channel segments wherein a power level of said center communication segment is less than said power levels of said first and second end communication segments.

37. A method of reducing a subscriber transmit power control range in a communication system having a base site and a subscriber, said method comprising the steps of:

measuring a signal strength of a signal received at said base site from said subscriber; and

selecting a communication channel of a plurality of communication channels, each of said plurality of communication channels serving substantially a single coverage area, within a single cell based upon said signal strength.

38. The method of claim 37 further comprising the step of sending said communication channel to said subscriber.