Common packet channel with firm handoff

• US 6,606,341 B1
• Filed: 05/04/1999
• Issued: 08/12/2003
• Est. Priority Date: 03/22/1999
• Status: Expired due to Term

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Golden Bridge Technology Incorporated
• Inventors: Parsa, Kourosh, Kanterakis, Emmanuel
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US09/304,345
• Time in Patent Office: 1,561 Days
• Field of Search: 375/140, 375/141, 375/130, 375/146, 375/147, 370/394, 370/342, 370/335, 370/320, 370/441, 370/445, 370/446, 370/447, 370/448, 455/436, 455/437, 455/439-444, 455/509
• US Class Current: 375/130
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• 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: H04B 7/2668 Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation, for code acquisition H04B1/7075, for code tracking H04B1/7085
• CPC Class Codes: H04J 13/0051 Orthogonal gold
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• 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 52/48 during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure

Abstract

An improvement to a code-division-multiple-access (CDMA) system employing spread-spectrum modulation, with the CDMA system having a base station (BS) and a plurality of remote stations. The base station has a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver. A remote station has an RS-spread-spectrum transmitter and an RS-spread-spectrum receiver. The BS transmitter transmits a broadcast common-synchronization channel, which includes a frame-timing signal. The broadcast common-synchronization channel has a common chip-sequence signal, which is common to the plurality of remote stations. In response to the RS-spread-spectrum receiver receiving the broadcast common-synchronization channel, and determining frame timing from the frame-timing signal, an RS-spread-spectrum transmitter transmits an access-burst signal, which includes, RS-power-control signals, transmitted in time, at increasing power levels. The BS-spread-spectrum transmitter, responsive to the BS-spread-spectrum receiver receiving the access-burst signal, and detecting an RS-preamble signal, transmits an acknowledgment signal. In response to the first RS-spread-spectrum receiver receiving the acknowledgment signal, the first RS-spread-spectrum transmitter transmits a spread-spectrum signal having data. The BS-spread-spectrum transmitter transmits either data or power-control information to the RS-spread-spectrum receiver.

Claims

1. A method of operating a mobile wireless code-division-multiple-access (CDMA) station to communicate data over a Common Packet Channel of a CDMA wireless network, the method comprising the steps of:

receiving a first frame-timing signal from a first CDMA base station over a broadcast synchronization channel;

receiving a second frame-timing signal from a second CDMA base station over a broadcast synchronization channel;

transmitting a first access burst signal over a CDMA Common Packet Channel, the first access burst signal comprising a first preamble code in a time slot selected from a plurality of time slots having predefined relationships to the first frame timing signal;

transmitting a second access burst signal over the CDMA Common Packet Channel, the second access burst signal comprising a second preamble code in a time slot selected from a plurality of time slots having predefined relationships to the second frame timing signal;

receiving an acknowledgement signal from at least the first CDMA base station;

selecting the first CDMA base station in response to the receiving of an acknowledgement signal; and

transmitting a CDMA signal comprising packet data and control information over the CDMA Common Packet Channel to the first CDMA base station.

2. A method as in claim 1, wherein upon selecting the first CDMA base station, the method further comprises:

receiving a plurality of power control signals from the first CDMA base station; and

transmitting a plurality of power control signals to the first CDMA base station.

3. A method as in claim 2, wherein the step of transmitting a CDMA signal comprising packet data and control information comprises transmitting at a rate determined in part in response to the received power control signals from the first CDMA base station.

4. A method as in claim 1, wherein:

the step of receiving an acknowledgement signal comprises receiving the acknowledgement signal from the first CDMA base and receiving an acknowledgement signal from the second CDMA base station; and

the first CDMA base station is selected in the selecting step because the wireless mobile CDMA station received the acknowledgement signal from the first CDMA base station before receiving the acknowledgement signal from the second CDMA base station.

5. A method as in claim 4, wherein:

the step of transmitting the first access burst signal comprises transmitting a sequence of first segments at increasing power levels, each first segment comprising the first preamble code; and

the step of transmitting the second access burst signal comprises transmitting a sequence of second segments at increasing power levels, each second segment comprising the second preamble code.

6. A method as in claim 1, wherein:

the step of receiving an acknowledgement signal comprises receiving the acknowledgement signal from the first CDMA base station and receiving an acknowledgement signal from the second CDMA base station; and

the first CDMA base station is selected in the step of selecting in response to a predetermined relationship of the received acknowledgement signals.

7. A method as in claim 6, wherein the predetermined relationship is that the acknowledgement signal from the first CDMA base station is received at a higher power level that the acknowledgement signal from the second CDMA base station.

8. A method as in claim 6, further comprising analyzing probabilities for errors with respect to the first and second base stations in response to the received acknowledgement signals, wherein the predetermined relationship is that the probability for errors is lower for the first CDMA base station.

9. A method as in claim 6, wherein:

the step of transmitting the first access burst signal comprises transmitting a sequence of first segments at increasing power levels, each first segment comprising the first preamble code; and

the step of transmitting the second access burst signal comprises transmitting a sequence of second segments at increasing power levels, each second segment comprising the second preamble code.

10. A method as in claim 1, wherein:

the step of receiving a first frame-timing signal comprises receiving the first frame timing signal over a first broadcast synchronization channel having a first common chip-sequence signal; and

the step of receiving a second frame-timing signal comprises receiving the second frame timing signal over a second broadcast synchronization channel having a second common chip-sequence signal.

11. A method as in claim 1, wherein the step of transmitting the CDMA signal comprising packet data comprises:

transmitting a selected collision detection code over the Common Packet Channel;

receiving a corresponding collision detection code from the first CDMA base station; and

initiating the transmission of the CDMA signal comprising packet data over the Common Packet Channel in response to the receipt of the corresponding collision detection code.

12. A code-division-multiple-access (CDMA) wireless mobile station, comprising:

a CDMA transmitter;

a CDMA receiver; and

a controller coupled to the CDMA receiver for responding to certain received signals and coupled for controlling the CDMA transmitter, such that in operation the wireless mobile station;

receives frame-timing signals from first and second CDMA base stations over at least one broadcast common-synchronization channel;

determines first and second frame timings from the received frame-timing signals;

transmits a first access burst signal comprising a first preamble code associated with the first CDMA base station over a Common Packet Channel at a time determined from the first frame timing signal;

transmits a second access burst signal comprising a second preamble code associated with the second CDMA base station over the Common Packet Channel at a time determined from the second frame timing signal;

receives an acknowledgement signal from at least the first CDMA base station;

selects the first CDMA base station in response to the receipt of an acknowledgement signal; and

transmits a CDMA signal comprising packet data and control information over the Common Packet Channel to the first CDMA base station.

13. A CDMA wireless mobile station as in claim 12, wherein the CDMA receiver receives the first timing signal over a first synchronization channel having a first common chip sequence, and the CDMA receiver receives the second timing signal over a second synchronization channel having a second common chip sequence.

14. A CDMA wireless mobile station as in claim 12, wherein the controller selects the first CDMA base station because the CDMA receiver receives only the acknowledgement signal from the first CDMA base station.

15. A CDMA wireless mobile station as in claim 12, wherein the controller selects the first CDMA base station because the CDMA receiver first receives the acknowledgement signal from the first CDMA base station before receiving an acknowledgement signal if any from the second CDMA base station.

16. A CDMA wireless mobile station as in claim 12, wherein:

the CDMA receiver receives the acknowledgement signal from the first CDMA base station and receives an acknowledgement signal from the second CDMA base station; and

the controller selects the first CDMA base station based on predetermined criteria with regard to the acknowledgement signals.

17. A CDMA wireless mobile station as in claim 16, wherein the controller selects the first CDMA base station because the acknowledgement signal from the first CDMA base station is received at a higher power level that the acknowledgement signal from the second CDMA base station.

18. A CDMA wireless mobile station as in claim 16, wherein the controller selects the first CDMA base station because analysis of the acknowledgement signals from the first and second CDMA base stations indicates a lower probability of errors for communications with the first CDMA base station.

19. A CDMA wireless mobile station as in claim 12, wherein the controller causes the CDMA transmitter to:

send the first access burst signal comprising a sequence of first segments transmitted at increasing power levels, each first segment comprising the first preamble code; and

send the second access burst signal comprising a sequence of second segments transmitted at increasing power levels, each second segment comprising the second preamble code.

20. A CDMA wireless mobile station as in claim 12, wherein the controller further causes the station to receive and respond to power control signals from the first CDMA base station and to transmit power control signals to the first CDMA base station.

21. A CDMA wireless mobile station as in claim 12, wherein the step of transmitting packet data comprises transmitting at a power-level determined in part from the received power control signals received from the first CDMA base station.

22. A CDMA wireless mobile station as in claim 12, wherein the controller causes the CDMA transmitter to transmit a selected collision detection code following receipt of the acknowledgement signal from the first CDMA base station and to initiate the transmission of the packet data in response to a subsequent receipt of a collision detection code from the first CDMA base station that corresponds to the selected collision detection code.

23. A method of transferring data for one of a plurality of wireless remote station (RS) handsets through one of a plurality base stations (BSs) of a wireless telecommunication network, each base station comprising a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver, the method comprising the steps of:

transmitting at least one frame timing signal from at least one BS-spread-spectrum transmitter over at least one broadcast common-synchronization channel having a common chip-sequence signal;

receiving the at least one broadcast common-synchronization channel at an RS-spread-spectrum receiver of the one RS handset and determining timing in response to the at least one frame timing signal;

transmitting from an RS-spread-spectrum transmitter of the one RS handset at least one access-burst signal comprising a plurality of segments containing a preamble code, in a predetermined timing relationship to the determined timing;

receiving at least one of the segments at the BS spread-spectrum receiver of at least one of the base stations;

transmitting an acknowledgment from a BS-spread-spectrum transmitter of each base station receiving at least one of the segments;

receiving one or more acknowledgments at said RS-spread-spectrum receiver;

selecting one of the base stations based on the received one or more acknowledgements;

transmitting a spread-spectrum signal comprising packet data and power control information from said RS-spread-spectrum transmitter for the selected base station; and

receiving the spread-spectrum signal comprising packet data and power control information at the BS-spread-spectrum receiver of the selected base station.

24. A method as in claim 23, wherein the step of transmitting at least one access-burst signal comprises transmitting segments at respective power levels, wherein each transmitted segment contains a preamble common to two or more of the base stations.

25. A method as in claim 24, wherein:

the step of receiving one or more acknowledgments comprises receiving a first acknowledgement from a first one of the base stations and receiving a second acknowledgement from a second one of the base stations; and

the step of selecting one of the base stations comprises analyzing the reception of the first and second acknowledgements to determine based on predetermined criteria which base station communication is best.

26. A method as in claim 25, wherein the predetermined criteria relates to relative power levels of the received acknowledgements.

27. A method as in claim 25, further comprising:

transmitting at least power control information for the one RS handset from the BS-spread-spectrum transmitter, at a power level determined in response to the power control information received from the one RS handsets;

receiving the power control information transmitted from the BS-spread transmitter in the one RS-spread-spectrum receiver; and

transmitting a spread-spectrum signal comprising packet data or power control information from the RS-spread spectrum transmitter, at a power level determined in response to the power control information received in the RS-spread spectrum receiver.

28. A method as in claim 23, wherein:

the step of transmitting at least one access-burst signal comprises;

transmitting a first plurality of segments containing a preamble associated with a first one of the base stations, and transmitting a second plurality of segments containing a second preamble associated with a second one of the base stations;

the step of receiving at least one of the segments comprises receiving at least one of the first plurality of segments at the BS-spread-Spectrum receiver of the first base station, and receiving at least one of the second plurality of segments at the BS-spread-spectrum receiver of the second base station; and

the step of transmitting an acknowledgment comprises transmitting a first acknowledgement corresponding to the first preamble from the BS-spread-spectrum transmitter of the first base station, and transmitting a second acknowledgement corresponding to the second preamble from the BS-spread-spectrum transmitter of the second base station.

29. A method as in claim 28, wherein the step of selecting one of the base stations comprises analyzing the reception of the first and second acknowledgements to determine based on predetermined criteria which base station communication is best.

30. A method as in claim 29, wherein the predetermined criteria relates to relative power levels of the received acknowledgements.

31. A method as in claim 29, wherein the predetermined criteria relates to which of the acknowledgements was received first at the RS-spread-spectrum receiver of the one RS handset.

32. A method as in claim 29, wherein the predetermined criteria relates to relative probabilities of errors in communication with respective base stations as determined from the received acknowledgements.

33. A method as in claim 23, further comprising:

transmitting a selected one of a plurality of collision-detection (CD) codes from said RS-spread-spectrum transmitter, upon selection of one of the base stations;

if the BS-spread-spectrum receiver of the selected base station detects the selected CD code, transmitting a selected one of a plurality of BS-CD codes from said BS-spread-spectrum transmitter of the selected base station; and

if the RS-spread-spectrum receiver detects the selected BS-CD code, initiating the step of transmitting the spread spectrum signal comprising packet data and power control information.

34. A method of providing a packet communication service in a code-division-multiple-access (CDMA) wireless network, comprising:

broadcasting a frame-timing signal from a CDMA base station of the network, over a common synchronization channel modulated with a common chip-sequence signal;

detecting an access burst from one of a plurality of remote CDMA stations received at the CDMA base station at an adequate power level, from among a plurality of access bursts transmitted from the one remote CDMA station at discretely different power levels;

selectively authorizing the one remote CDMA station to use an uplink channel for packet transmissions to the CDMA base station, on a slotted-aloha basis, in a predetermined relationship to the frame-timing signal;

receiving power control signals followed immediately by data signals, over the uplink channel, from the one authorized remote CDMA station, at the CDMA base station; and

transmitting power control signals intended for the one authorized remote CDMA station, from the CDMA base station, at a power level based on the received power control signals.

35. A method as in claim 34, further comprising transmitting additional signals intended for the one authorized remote CDMA station at power levels based on the received power control signals.

36. A code-division-multiple-access (CDMA) wireless base station, the base station being assigned a set of possible coded preamble signals for use in CDMA communications, the CDMA base station comprising:

a CDMA transmitter;

a CDMA receiver; and

a controller coupled to the CDMA receiver for responding to certain received signals and coupled for control of the CDMA transmitter, such that in operation the CDMA base station;

receives from a remote station a detectable access burst, from among a plurality of access bursts transmitted from the one remote station at discretely different power levels, the detectable access burst comprising one of the possible coded preamble signals assigned to the base station selected by the remote station;

sends a coded acknowledgement signal over a control channel, the coded acknowledgement signal corresponding to the received coded preamble signal;

receives power control signals and data from the remote station after transmission of the acknowledgement signal; and

transmits signals intended for the remote station at power levels based on the received power control signals.

37. A CDMA base station as in claim 36, wherein:

the reception of data over the Common Packet Channel from the remote station comprises receiving a coded collision detection signal;

upon receipt of the coded collision detection signal, the controller causes the CDMA base station to transmit back over the control channel a corresponding coded collision detection signal; and

the reception of power control and data signals over the Common Packet Channel from the remote station further comprises receiving the power control and data signals after transmission of the corresponding coded collision detection signal.

38. A CDMA base station as in claim 36, wherein the controller causes the CDMA transmitter to broadcast a frame-timing signal over a common synchronization channel modulated with a common chip-sequence signal.

39. A CDMA base station as in claim 38, wherein the CDMA receiver receives the access burst in one of a plurality of access slots defined in relation to the frame-timing signal.

40. A CDMA base station as in claim 36, wherein:

the reception of a detectable access burst comprises receiving one or more coded preamble signals that may be transmitted at sequentially increasing discrete power levels; and

the controller causes the CDMA transmitter to transmit the acknowledgement signal in response to a first coded preamble signal that is received at an adequate power level.

41. A code-division-multiple-access (CDMA) wireless mobile station, comprising:

a CDMA transmitter;

a CDMA receiver; and

a controller coupled to the CDMA receiver for responding to certain received signals and coupled for controlling the CDMA transmitter, such that in operation the wireless mobile station;

receives a frame-timing signal from a CDMA base station over a broadcast common-synchronization channel having a common chip-sequence signal;

determines frame timing from the received frame-timing signal;

transmits a plurality of access burst signals at sequentially increasing discrete power levels, in one or more time slots selected from a plurality of time slots having predefined relationships to the determined frame timing;

receives an acknowledgement signal corresponding to the access burst signal, from the CDMA base station;

receives power control signals and data from the CDMA base station;

transmits power control signals to the CDMA base station at power levels based on the received power control signals, following receipt of the acknowledgement signal; and

transmits packet data to the CDMA base station at power levels based on the received power control signals.

42. A CDMA wireless mobile station as in claim 41, wherein the controller causes the CDMA transmitter to transmit the power control signals to the CDMA base station immediately prior to the transmission of the packet data.

43. A CDMA wireless mobile station as in claim 41, wherein the controller causes the CDMA transmitter to transmit a selected collision detection code following receipt of the acknowledgement signal and initiates transmission of at least the packet data in response to receipt of a collision detection code from the CDMA base station that corresponds to the selected collision detection code.

44. CDMA wireless mobile station as in claim 43, wherein the controller causes the CDMA transmitter to transmit the power control signals to the CDMA base station following receipt of the corresponding collision detection code from the CDMA base station and subsequently causes the CDMA transmitter to transmit the packet data.

45. A method of transferring data for one of a plurality of wireless remote station (RS) handsets through a base station (BS) of a wireless telecommunication network, the base station comprising a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver, the method comprising the steps of:

transmitting a frame-timing signal from said BS-spread-spectrum transmitter over a broadcast common-synchronization channel having a common chip-sequence signal;

receiving the broadcast common-synchronization channel comprising a frame timing signal at an RS-spread-spectrum receiver of the one RS handset;

determining frame timing at an RS-spread-spectrum receiver of the one RS handset from the received frame-timing signal;

transmitting segments of an access-burst signal from an RS-spread-spectrum transmitter of the one RS handset at sequentially increasing discrete power levels, wherein timing of the one or more segments is based on the determined frame timing;

receiving at least one segment of the access-burst signal at said BS spread-spectrum receiver;

transmitting an acknowledgment from said BS-spread-spectrum transmitter, in response to the receipt of the at least one segment of the access-burst signal;

transmitting a spread-spectrum signal comprising power control information from said BS-spread-spectrum transmitter, after transmitting the acknowledgment;

receiving the acknowledgment and the power control information at said RS-spread-spectrum receiver;

transmitting a spread-spectrum signal comprising power control information and packet data from said RS-spread-spectrum transmitter, in response to the receipt of the acknowledgment and at a power level responsive to the received power control information;

receiving the spread-spectrum signal comprising power control information and packet data from said RS-spread-spectrum transmitter, at said BS-spread-spectrum receiver;

forwarding the received data from said base station to another network element; and

transmitting from said BS-spread-spectrum transmitter additional signals intended for said RS-spread-spectrum receiver at power levels determined at least in part in response to the power control information received at said BS-spread-spectrum receiver.

46. The method as set forth in claim 45, wherein the step of receiving at least one segment comprises receiving at least one segment at a detectable power level.

47. The method as set forth in claim 45, wherein each segment comprises a selected one of a plurality of preamble codes, and the acknowledgement comprises a coded signal corresponding to the selected preamble code.

48. The method as set forth in claim 45, further comprising:

transmitting a selected one of a plurality of collision-detection (CD) codes by said RS-spread-spectrum transmitter, in response to receipt of the acknowledgment;

if the BS-spread-spectrum receiver detects the selected CD code from the RS-spread-spectrum transmitter, transmitting a corresponding BS-CD code from said BS-spread-spectrum transmitter; and

if the RS-spread-spectrum receiver detects the corresponding BS-CD code, transmitting at least data to said base station, from said RS-spread-spectrum transmitter.

49. The method as set forth in claim 48, wherein the step of transmitting at least data comprises transmitting the power control signals followed by the data, to said base station, from said RS-spread-spectrum transmitter.