Hybrid DSMA/CDMA (digital sense multiple access/code division multiple access) method with collision resolution for packet communications

• US 7,075,971 B2
• Filed: 10/14/2003
• Issued: 07/11/2006
• Est. Priority Date: 10/26/1999
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Golden Bridge Technology Incorporated
• Inventors: Kanterakis, Emmanuel, Parsa, Kourosh
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US10/682,985
• Publication Number:
  US 20040081115A1
• Time in Patent Office: 1,001 Days
• Field of Search: 375/141, 375/130, 375/146, 375/147, 370/342, 370/320, 370/441, 370/329, 370/335, 455/509
• US Class Current: 375/141
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0075 Transmission of coding parameters to receiver H04L1/0023 takes precedence
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1877 for semi-reliable protocols, e.g. for less sensitive applications like streaming video buffer level management for video bitstream control arrangements H04N21/44004
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 74/085 collision avoidance

Abstract

A hybrid DSMA-CR/CDMA methodology provides efficient access to one of a group of packet channels in a spread spectrum wireless communication network. The base station broadcasts status information as to the availability and/or available data rates for each packet channel or group of channels. Each mobile station uses the status information to select an available channel and/or a channel with sufficient data rate. The mobile station then starts transmission of a series of access preambles, each of which contains a signature corresponding to the selected channel. The mobile station transmits the preambles at increasing power levels. When the base station detects a preamble transmission, the base station responds with a corresponding acknowledgement essentially permitting the mobile station to send its packet data along with any closed-loop power control information over the selected channel.

Claims

1. In a wireless communication system employing spread-spectrum modulation comprising a plurality of base stations and a plurality of mobile stations, a method comprising:

transmitting from a BS-spread-spectrum transmitter of one base station, a broadcast common-status channel, the broadcast common-status channel comprising data regarding current status as available for one or more channels from among a group of channels associated with the one base station;

receiving the broadcast common-status channel at a MS-spread-spectrum receiver of one mobile station, and selecting one of the channels of the group based on the broadcast available status data;

transmitting from a MS-spread-spectrum transmitter of the one mobile station an access-burst signal to request access to the selected channel, the access-burst signal comprising a plurality of segments having a plurality of respective power levels;

receiving at a BS spread-spectrum receiver of the one base station at least one segment of the access-burst signal at a detectable-power level;

responsive to receipt of the at least one segment at the detectable power level, transmitting an acknowledgment signal from the BS-spread-spectrum transmitter of the one base station;

receiving the acknowledgment signal at the MS-spread-spectrum receiver of the one mobile station; and

transmitting from the MS-spread-spectrum transmitter of the one mobile station a spread-spectrum signal comprising at least one of data and power control information, over the selected channel, responsive to the receipt of the acknowledgment signal.

2. The method of claim 1, wherein the selected channel is a common packet channel.

3. The method of claim 1, wherein:

a transmission from the BS-spread-spectrum transmitter of the one base station intended for the one mobile station utilizes a downlink channel corresponding to the selected channel; and

if the MS-spread-spectrum receiver of the one mobile station detects a loss of the downlink channel, the MS-spread-spectrum receiver of the one mobile station halts any further transmission over the selected channel.

4. The method of claim 1, further comprising a collision resolution phase executed between the receipt of the acknowledgment signal and the transmission by the one mobile station over the selected channel.

5. The method of claim 4, wherein the collision resolution phase comprises:

transmitting from the MS-spread-spectrum transmitter of the one mobile station a spread-spectrum signal comprising a collision detection preamble;

receiving the collision detection preamble from the one mobile station at the BS spread-spectrum receiver of the one base station and substantially concurrently receiving a collision detection preamble from another mobile station at the BS spread-spectrum receiver of the one base station;

selecting the one mobile station for assignment of the selected channel;

transmitting from the BS-spread-spectrum transmitter of the one base station a base station collision detection preamble, the base station collision detection preamble corresponding to the collision detection preamble from the one mobile station; and

receiving the base station collision detection preamble at the MS-spread-spectrum receiver of the one mobile station,

wherein the step of transmitting the spread-spectrum signal comprising one or more of data and power control information from the MS-spread-spectrum transmitter of the one mobile station over the selected channel is responsive to the receipt of the base station collision detection preamble.

6. The method of claim 1, wherein each segment of the access burst signal comprises a selected one of a group of access preamble signatures, the selected one signature corresponding to the selected channel.

7. The method of claim 6, wherein the acknowledgement signal corresponds to the selected one signature.

8. The method of claim 1, wherein the data regarding current status indicates an idle status for at least one channel from among a group of channels associated with the one base station.

9. The method of ciaim 1, wherein the step of transmitting over the selected channel comprises:

transmitting a first packet that is ready to send over the selected channel; and

piggybacking at least one additional packet that becomes ready-to-send immediately after transmission of the first data packet.

10. A method of allowing access to a channel of a wireless communication network, comprising:

transmitting a broadcast common-status channel, the broadcast common-status channel comprising availability-related status information for one or more channels of a group of packet channels allocated to a base station of the network;

receiving from a remote station an access burst, the access burst comprising a sequence of coded preamble signals at sequentially increasing discrete power levels, each coded preamble signal in the sequence comprising one of a plurality of possible signature codes, the one signature code corresponding to one of the packet channels selected from the group by the remote station based on the status information;

detecting a first one of the coded preamble signals of the sequence that is received at an adequate power level; and

upon detection of the first coded preamble signal at the adequate power level, transmitting an acknowledgement signal corresponding to the one signature code.

11. The method of claim 10, further comprising receiving any of data and power control information over the one packet channel from the remote station after the transmitting of the acknowledgement signal.

12. The method of claim 11, wherein the one packet channel is a common packet channel.

13. The method of claim 10, further comprising:

receiving from the remote station a first remote station collision detection preamble;

substantially concurrently receiving from another remote station a second remote station collision detection preamble; and

transmitting a base station collision detection preamble corresponding to the first remote station collision detection preamble.

14. The method of claim 13, further comprising performing a power control phase after transmitting the base station collision detection preamble and before receiving the any data over the one packet channel.

15. The method of claim 10, further comprising sending any of data and power control information for the remote station.

16. The method of claim 10, wherein the availability-related status information comprises at least one of:

data regarding availability of one or more channels from among the group of packet channels allocated to the base station, and

data regarding available data rates for one or more channels of the group of packet channels allocated to the base station.

17. A method of accessing a channel of a wireless communication network, comprising:

receiving a broadcast common-status channel from a base station of the network, the broadcast common-status channel comprising availability-related status information for one or more channels of a group of packet channels served through the base station;

selecting one packet channel from the group based on the status information;

transmitting an access burst, the access burst comprising a sequence of coded preamble signals at sequentially increasing discrete power levels, each coded preamble signal in the sequence comprising one of a plurality of possible signature codes, the one signature code corresponding to the selected packet channel;

receiving an acknowledgement signal from the base station over a downlink channel corresponding to the one packet channel following the transmission of one or more of the coded preamble signals, the acknowledgement signal corresponding to the signature code; and

transmitting any of data and power control information over the one packet channel following receipt of the acknowledgement signal.

18. The method of claim 17, further comprising receiving any of data and control information from the base station over a downlink channel corresponding to the one packet channel.

19. The method of claim 18, further comprising:

detecting a loss of the downlink channel; and

in response to detecting loss of the downlink channel, halting any further transmission over the one packet channel.

20. The method of claim 17, the one packet channel is a common packet channel.

21. The method of claim 17, further comprising:

transmitting a randomly generated remote station collision detection preamble upon receipt of the acknowledgement signal; and

receiving a base station collision detection preamble corresponding to the remote station collision detection preamble,

wherein the step of transmitting over the one packet channel follows the receipt of the corresponding base station collision detection preamble.

22. The method of claim 17, wherein the received availability-related status information comprises at least one of:

data regarding availability of one or more channels from among the group of packet channels served through the base station; and

data regarding available data rates for one or more channels of the group of packet channels served through the base station.

23. The method of claim 17, wherein:

the selecting of the one packet channel occurs when the remote station has a first data packet to send, and

the transmitting over the one packet channel comprises;

transmitting the first data packet over the one packet channel following receipt of the acknowledgement signal; and

piggy-backing at least one additional packet that becomes ready-to-send immediately after transmission of the first data packet.

24. In a wireless communication system employing spread-spectrum modulation comprising a plurality of base stations and a plurality of mobile stations, a method comprising:

transmitting from a BS-spread-spectrum transmitter of one base station, a broadcast common-status channel, the broadcast common-status channel comprising data regarding available data rates for one or more channels of a group of channels associated with the one base station;

receiving the broadcast common-status channel at a MS-spread-spectrum receiver of one mobile station, and selecting one of the channels of the group based on the available data rates data;

transmitting from a MS-spread-spectrum transmitter of the one mobile station an access-burst signal to request access to the selected channel, the access-burst signal comprising a plurality of segments having a plurality of respective power levels;

receiving at a BS spread-spectrum receiver of the one base station at least one segment of the access-burst signal at a detectable-power level;

responsive to receipt of the at least one segment at the detectable power level, transmitting an acknowledgment signal from the BS-spread-spectrum transmitter of the one base station;

receiving the acknowledgment signal at the MS-spread-spectrum receiver of the one mobile station; and

transmitting from the MS-spread-spectrum transmitter of the one mobile station a spread-spectrum signal comprising at least one of data and power control information, over the selected channel, responsive to the receipt of the acknowledgment signal.

25. The method of claim 24, wherein the selected channel is a common packet channel.

26. The method of claim 24, further comprising transmitting any of data and power control information, to the MS-spread-spectrum receiver, from the BS-spread-spectrum transmitter of the one base station.

27. The method of claim 24, wherein the broadcast common-status channel further comprises data regarding the availability of one or more channels from among the group of channels associated with the one base station.