Methods and apparatuses for fast power control of signals transmitted on a multiple access channel

• US 6,252,865 B1
• Filed: 10/02/1998
• Issued: 06/26/2001
• Est. Priority Date: 10/02/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Howard, Steven J., Ketchum, John W., Wallace, Mark S., Walton, Jay R.
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Vanderpuye, Ken
• Application Number:
  US09/165,858
• Time in Patent Office: 998 Days
• Field of Search: 370/329, 370/331, 370/322, 370/335, 370/337, 370/342, 370/347, 370/349, 370/449, 370/252, 455/450, 455/451-3, 455/501, 455/517, 455/522, 455/134, 711/216
• US Class Current: 370/335
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A method and apparatus for controlling the transmission of signals from one or more of a plurality of mobile stations to a base station on a plurality of M multiple access channels. A power control information packet formed from a plurality of power control bits is transmitted from the base station to the one or more mobile stations. Each of the power control bits in the power control information packet has a position that is mapped to a selected access channel and to a time offset within the selected access channel. The power control information packet is received at a first mobile station. A message is then transmitted from the first mobile station to the base station on a first access channel and at a first time offset associated with the first access channel. The message is transmitted from the first mobile station at a power level determined in response to a first power control bit in the power control information packet. The first power control bit is located in a first position in the power control information packet, the first position being mapped to the first access channel and the first time offset.

Claims

1. A method for determining whether a mobile station which is attempting to access a multiple access channel has gained access to the multiple access channel, including the steps of:

a) generating a hashing value from information particular to the mobile station;

b) transmitting the hashing value from the mobile station over the multiple access channel if the multiple access channel is not busy;

c) monitoring a received signal to determine whether the hashing value has been echoed back to the mobile station;

d) checking for a received power control bit, whose presence indicates that the multiple access channel is busy; and

e) continuing to transmit over the multiple access channel only if the hashing function is echoed back to the mobile station within a predetermined amount of time.

8. The method of claim 1, wherein the power control bit comprises a plurality of states.

9. The method of claim 8, wherein a first state of the plurality of states initiates the transmission of message information from the mobile station.

10. The method of claim 8, wherein a second state of the plurality of states inhibits the initiation of transmission of message information from the mobile station.

11. The method of claim 8, wherein a third state of the plurality of states ceases transmission of message information from the mobile station.

12. The method of claim 8, wherein a second state of the plurality of states increases an output power level of the mobile station.

13. The method of claim 8, wherein a third state of the plurality of states decreases an output power level of the mobile station.

2. A method for indicating whether a mobile station which is attempting to access a multiple access channel has gained access to the multiple access channel, including the steps of:

a) receiving a request to access the multiple access channel, the request including a hashing value indicating the identity of the mobile station;

b) checking for a received power control bit, whose presence indicates that the multiple access channel is busy;

c) assigning the multiple access channel to the hashing value only if the multiple access channel is not busy; and

e) broadcasting a message from the base station, the message including the hashing value received with the request.

3. The method of claim 2, further including the steps of:

a) receiving a preamble from the mobile station; and

b) transmitting an initial power adjustment word using pre-assigned bits of a sub-mini-slot in response to a power level of the preamble, wherein at least one of the pre-assigned bits of the initial power adjustment word is pre-assigned to echoing the hash value received from the mobile station once the hash value has been received.

14. The method of claim 2, wherein the power control bit comprises a plurality of states.

15. The method of claim 14, wherein a first state of the plurality of states initiates the transmission of message information from the mobile station.

16. The method of claim 14, wherein a second state of the plurality of states inhibits the initiation of transmission of message information from the mobile station.

17. The method of claim 14, wherein a third state of the plurality of states ceases transmission of message information from the mobile station.

18. The method of claim 14, wherein a second state of the plurality of states increases an output power level of the mobile station.

19. The method of claim 14, wherein a third state of the plurality of states decreases an output power level of the mobile station.

4. A method for accessing a multiple access channel, including the steps of:

a) transmitting a request to access the multiple access channel, the request including a hashing value indicating the identity of a mobile station;

b) checking for a received power control bit, whose presence indicates that the multiple access channel is busy;

c) receiving a message from the base station, the message including the hashing value received with the request.

5. The method of claim 4, further including the steps of:

a) transmitting a preamble from the mobile station; and

b) receiving an initial power adjustment word using pre-assigned bits of a sub-mini-slot, wherein at least one of the pre-assigned bits of the initial power adjustment word is pre-assigned to echoing the hash value received from the mobile station once the hash value has been received.

6. The method of claim 4, further including the steps of:

a) transmitting a preamble from the mobile station;

b) ceasing transmission;

c) receiving an initial power control adjustment word; and

d) resuming transmission, the power of the resumed transmission being adjusted in response to the value of the received initial power control adjustment word.

7. The method of claim 6, further including the step of transmitting a rate word before ceasing transmission.

20. A method for determining whether a mobile station which is attempting to access a multiple access channel has gained access to the multiple access channel, comprising:

a) generating a hashing value from information particular to the mobile station;

b) transmitting the hashing value from the mobile station over the multiple access channel if the multiple access channel is not busy;

c) monitoring a received message for a power control bit, whose presence that the multiple access channel is busy;

d) monitoring the received message to determine whether the hashing value has been echoed back to the mobile station; and

e) initiating transmission over the multiple access channel only if the multiple access channel is not busy and the hashing function is echoed back to the mobile station within a predetermined amount of time.

21. The method of claim 20, further comprising continuing to transmit over the multiple access channel only if the hashing function is echoed back to the mobile station within a predetermined amount of time.

22. The method of claim 20, further comprising:

a) receiving a preamble from the mobile station; and

b) transmitting an initial power adjustment word using pre-assigned bits of a sub-mini-slot in response to a power level of the preamble, wherein at least one of the pre-assigned bits of the initial power adjustment word is pre-assigned to echoing the hash value received from the mobile station once the hash value has been received.