Reservation multiple access

• US 6,788,937 B1
• Filed: 03/24/1999
• Issued: 09/07/2004
• Est. Priority Date: 10/15/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Vanghi, Vieri, Walton, Rod J., Willenegger, Serge
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): ZEWDU, MELESS NMN
• Application Number:
  US09/275,729
• Time in Patent Office: 1,994 Days
• Field of Search: 370/328, 370/329, 370/335, 370/342, 370/343, 370/348, 370/318, 370/320, 370/322, 370/462, 370/445, 370/447, 370/461, 370/443, 370/444, 370/437, 455/434, 455/435.2, 455/450, 455/455, 455/515-517
• US Class Current: 455/434
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

A mobile station accesses a base station by randomly selecting a first reverse link common control channel from a set of random access channels. The mobile station transmits a request portion of an access probe over the first reverse link common control channel. The request portion is subject to collision with other signals. The request portion comprises a hash identification which is derived from a uniquely identifying number using a hash function. The hash identification quasi-uniquely identifies the mobile station. The mobile station receives a channel assignment message from the base station designating the hash identification and a reserved access channel. The reserved access channel provides communication with a low probability of contention. The mobile station transmits a message portion of the access probe over the reserved access channel.

Claims

1. In a communication system, a method of accessing a base station from a mobile station, comprising:

selecting a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

transmitting a request portion of an access probe over a reverse link common control channel subject to contention, said access probe modulated with said signature sequence;

receiving a channel assignment message from said base station designating a reserved access channel, said reserved access channel providing communication with a low probability of contention and said channel assignment message reflecting said first signature;

transmitting a message portion of said access probe over said reserved access channel, wherein said transmitting said message portion facilitates reception of said message portion by a plurality of base stations;

receiving a power control command over a forward link channel associated with said reserved access channel; and

responding to said power control command by increasing or decreasing a power level at which said mobile station transmits said message portion.

2. The method of claim 1, wherein said message portion comprises an overhead message.

3. The method of claim 1, wherein said message portion comprises user data.

4. The method of claim 1, wherein said transmitting said message portion occurs at one of a plurality of available data rates.

7. The method of claim 1, wherein said request portion comprises an identification which quasi-uniquely identifies said mobile station.

8. The method of claim 7, further comprising determining said identification which quasi-uniquely identifies said mobile station from a unique identifying number associated with said mobile station using a hash function.

9. The method of claim 7, further comprising randomly selecting said identification which quasi-uniquely identifies said mobile station.

16. The method of claim 1, wherein said forward link channel is expressly specified in said channel assignment message.

5. In a communication system, a method of accessing a base station from a mobile station, comprising:

selecting a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

transmitting a request portion of an access probe over a reverse link common control channel subject to contention, said access probe modulated with said signature sequence;

receiving a channel assignment message from said base station designating a reserved access channel, said reserved access channel providing communication with a low probability of contention and said channel assignment message reflecting said first signature;

transmitting a message portion of said access probe over said reserved access channel, wherein said message portion comprises a call origination message;

receiving a power control command over a forward link channel associated with said reserved access channel; and

responding to said power control command by increasing or decreasing a power level at which said mobile station transmits said message portion.

6. In a communication system, a method of accessing a base station from a mobile station, comprising:

selecting a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

transmitting a request portion of an access probe over a reverse link common control channel subject to contention, said access probe modulated with said signature sequence;

receiving a channel assignment message from said base station designating a reserved access channel, said reserved access channel providing communication with a low probability of contention and said channel assignment message reflecting said first signature;

transmitting a message portion of said access probe over said reserved access channel, wherein said message portion is longer than said request portion;

receiving a power control command over a forward link channel associated with said reserved access channel; and

responding to said power control command by increasing or decreasing a power level at which said mobile station transmits said message portion.

10. In a communication system, a method of accessing a base station from a mobile station, comprising:

selecting a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

transmitting a request portion of an access probe over a reverse link common control channel subject to contention, said access probe modulated with said signature sequence;

receiving a channel assignment message from said base station designating a reserved access channel, said reserved access channel providing communication with a low probability of contention and said channel assignment message reflecting said first signature and specifying a wait period to be observed;

transmitting a message portion of said access probe over said reserved access channel;

receiving a power control command over a forward link channel associated with said reserved access channel;

responding to said power control command by increasing or decreasing a power level at which said mobile station transmits said message portion; and

delaying said transmitting said message portion with reference to said wait period.

11. In a communication system, a method of accessing a base station from a mobile station, comprising:

selecting a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

transmitting a request portion of an access probe over a reverse link common control channel subject to contention, said access probe modulated with said signature sequence;

receiving a channel assignment message from said base station designating a reserved access channel, said reserved access channel providing communication with a low probability of contention and said channel assignment message reflecting said first signature and specifying a power control information;

transmitting a message portion of said access probe over said reserved access channel;

receiving a power control command over a forward link channel associated with said reserved access channel; and

responding to said power control command by increasing or decreasing a power level at which said mobile station transmits said message portion; and

determining a power level at which to transmit said message portion with reference to said power control information.

12. The method of claim 11, wherein said channel assignment message is spread with a second spreading sequence, said second spreading sequence reflecting said first signature.

13. The method of claim 12, wherein a polarity of said second spreading sequence conveys mobile station information.

14. The method of claim 13, wherein said mobile station information is power control information.

15. The method of claim 13, wherein said mobile station information is data rate information.

17. In a communication system, a method of accessing a base station from a mobile station, comprising:

selecting a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

transmitting a request portion of an access probe over a reverse link common control channel subject to contention, said access probe modulated with said signature sequence;

receiving a channel assignment message from said base station designating a reserved access channel, said reserved access channel providing communication with a low probability of contention and said channel assignment message reflecting said first signature;

transmitting a message portion of said access probe over said reserved access channel;

receiving a power control command over a forward link channel associated with said reserved access channel; and

responding to said power control command by increasing or decreasing a power level at which said mobile station transmits said message portion;

receiving a message from said base station modulated with a predetermined sequence, said predetermined sequence reflecting a level of loading at said base station.

18. A mobile communication station, comprising:

a controller configured to generate a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

a modulator coupled to said controller, said modulator being configured to modulate a request portion of an access probe with said first signature sequence and to modulate a message portion of said access probe;

a radio frequency signal processing unit coupled to said modulator, said signal processing unit being configured to transmit said request portion over a forward link common control channel subject to contention and configured to receive a channel assignment message reflecting said first signature and a reserved access channel, said reserved access channel providing communication with a low probability of contention and configured to transmit said modulated message portion over said reserved access channel, said radio frequency signal processing unit comprising;

a power control apparatus configured to receive a power control command over a forward link channel and configured to respond thereto by increasing or decreasing a power level at which said mobile station transmits said message portion; and

a demodulator coupled to said radio frequency signal processing unit and said controller, said demodulator configured to demodulate said channel assignment message according to a second signature sequence associated with said first signature sequence.

19. A mobile communication station, comprising:

a controller configured to generate a first signature sequence from a plurality of signature sequences used by multiple mobile stations;

a modulator coupled to said controller, said modulator being configured to modulate a request portion of an access probe with said first signature sequence and to modulate a message portion of said access probe;

a radio frequency signal processing unit coupled to said modulator, said signal processing unit being configured to transmit said request portion over a forward link common control channel subject to contention and configured to receive a channel assignment message reflecting said first signature and a reserved access channel, said reserved access channel providing communication with a low probability of contention and configured to transmit said modulated message portion over said reserved access channel, said radio frequency signal processing unit comprising;

a power control apparatus configured to receive a power control command over a forward link channel and configured to respond thereto by increasing or decreasing a power level at which said mobile station transmits said message portion, wherein said radio frequency signal processing unit is further configured to receive said power control command from a plurality of sectors associated with a single base station; and

a demodulator coupled to said radio frequency signal processing unit and said controller, said demodulator configured to demodulate said channel assignment message.

20. A method of communication system access, comprising:

receiving a request portion of an access probe modulated with a first signature sequence selected from among a plurality of signature sequences which provide communication subject to contention;

transmitting a channel assignment message designating said first signature sequence and a reserved access channel, said reserved access channel providing communication with a low probability of contention;

receiving a message portion of said access probe over said reserved access channel from a mobile station, wherein said channel assignment message specifies a wait period to be observed before said receiving said message portion is executed; and

transmitting a power control command over a forward link channel based upon a signal quality level at which said message portion is received during said receiving said message portion.

21. The method of claim 20, wherein said step of receiving said message portion is performed by a plurality of sectors associated with a base station.

22. The method of claim 20, wherein said request portion comprises an identification which quasi-uniquely identifies said mobile station.

23. A method of communication system access, comprising:

receiving a request portion of an access probe modulated with a first signature sequence selected from among a plurality of signature sequences which provide communication subject to contention;

transmitting a channel assignment message designating said first signature sequence and a reserved access channel, said reserved access channel providing communication with a low probability of contention;

receiving a message portion of said access probe over said reserved access channel from a mobile station; and

transmitting a power control command over a forward link channel based upon a signal quality level at which said message portion is received during said receiving said message portion;

determining a power correction amount based upon a signal quality level at which said request portion is received and wherein said channel assignment message specifies said power control correction amount to be used by said mobile station to transmit said message portion.

24. The method of claim 23, further comprising the step of transmitting a power control command through a plurality of sectors associated with said base station, said transmitting step being performed in response to a signal quality level at which said message portion is received.

25. A method of communication system access, comprising:

receiving a request portion of an access probe modulated with a first signature sequence selected from among a plurality of signature sequences which provide communication subject to contention;

transmitting a channel assignment message designating said first signature sequence and a reserved access channel, said reserved access channel providing communication with a low probability of contention, and wherein said transmitting said channel assignment message includes modulating said channel assignment message with a second signature sequence, said second signature sequence associated with said first signature sequence;

receiving a message portion of said access probe over said reserved access channel from a mobile station; and

transmitting a power control command over a forward link channel based upon a signal quality level at which said message portion is received during said receiving said message portion.

26. A method of communication system access, comprising:

receiving a request portion of an access probe modulated with a first signature sequence selected from among a plurality of signature sequences which provide communication subject to contention;

transmitting a channel assignment message designating said first signature sequence and a reserved access channel, said reserved access channel providing communication with a low probability of contention;

receiving a message portion of said access probe over said reserved access channel from a mobile station;

transmitting a power control command over a forward link channel based upon a signal quality level at which said message portion is received during said receiving said message portion; and

transmitting a loading message modulated with a spreading sequence which reflects a level of loading at a base station.