Common packet channel with firm handoff

• US 6,985,511 B2
• Filed: 06/27/2003
• Issued: 01/10/2006
• Est. Priority Date: 03/22/1999
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Golden Bridge Technology Incorporated
• Inventors: Kanterakis, Emmanuel, Parsa, Kourosh
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US10/607,342
• Publication Number:
  US 20050117549A1
• Time in Patent Office: 928 Days
• Field of Search: 370/130, 370/141, 370/140, 370/342, 370/347, 370/208, 370/209, 370/337, 370/335, 370/503, 370/506, 370/514, 370/445, 370/374, 370/525, 370/526, 370362-368, 455/522, 455/422
• US Class Current: 375/141
• 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 baseband processor for a wireless mobile station, comprising:

a spread-spectrum transceiver for transmitting and receiving wireless spread-spectrum signals;

an acknowledgment detector for detecting an acknowledgment in a received spread-spectrum signal;

a data and control processor, for detecting and processing data and control information contained in a received spread-spectrum signal;

a preamble generator for generating preamble signals;

a multiplexer, for multiplexing data and the preamble signals;

a packet formatter, coupled to the multiplexer, for formatting the multiplexed data and preamble signals into packets for wireless transmission; and

a controller, responsive to the acknowledgement detector, for controlling the transceiver the preamble generator, the multiplexer and the packet formatter, such that in operation the baseband processor;

receives frame-timing signals from first and second 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 base station 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 base station at a time determined from the second frame timing signal;

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

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

transmits a signal comprising packet data and control information over an uplink channel to the first base station.

2. The baseband processor as in claim 1, wherein the transceiver receives the first timing signal over a first synchronization channel having a first common chip sequence, and the transceiver receives the second timing signal over a second synchronization channel having a second common chip sequence.

3. The baseband processor as in claim 1, wherein the controller selects the first base station because the transceiver receives only the acknowledgement signal from the first base station.

4. The baseband processor as in claim 1, wherein the controller selects the first base station because the transceiver first receives the acknowledgement signal from the first base station before receiving an acknowledgement signal if any from the second base station.

5. The baseband processor as in claim 1, wherein:

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

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

6. The baseband processor as in claim 5, wherein the controller selects the first base station because the acknowledgement signal from the first base station is received at a higher power level than the acknowledgement signal from the second base station.

7. The baseband processor as in claim 5, wherein the controller selects the first base station because analysis of the acknowledgement signals from the first and second base stations indicates a lower probability of errors for communications with the first base station.

8. The baseband processor as in claim as in claim 1, wherein the controller causes the transceiver 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.

9. The baseband processor as in claim 1, wherein the controller further causes the transceiver to receive and respond to power control signals from the first base station and to transmit power control signals to the first base station.

10. The baseband processor as in claim 1, wherein the transmission of the signal comprising packet data comprises transmitting at a power-level determined in part from power control signals received from the first base station.

11. The baseband processor as in claim 1, wherein the controller causes the transceiver to transmit a selected collision detection code following receipt of the acknowledgement signal from the first base station and to initiate the transmission of the signal comprising packet data in response to a subsequent receipt of a collision detection code from the first base station that corresponds to the selected collision detection code.

12. A baseband processor for a wireless mobile station, comprising:

a spread-spectrum transceiver for transmitting and receiving wireless spread-spectrum signals;

an acknowledgment detector for detecting an acknowledgment in a received spread-spectrum signal;

a data and control processor, for detecting and processing data and control information contained in a received spread-spectrum signal;

a preamble generator for generating preamble signals;

a multiplexer for multiplexing data and the preamble signals;

a packet formatter, coupled to the multiplexer, for formatting the multiplexed data and preamble signals into packets for wireless transmission; and

a controller, responsive to the acknowledgment detector, for controlling the transceiver, the preamble generator, the multiplexer and the packet formatter, such that in operation the baseband processor;

receives a frame-timing signal from a 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 base station;

receives power control signals and data from the base station;

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

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

13. The baseband processor as in claim 12, wherein the controller causes the transceiver to transmit the power control signals to the base station immediately prior to the transmission of the packet data.

14. The baseband processor as in claim 12, wherein the controller causes the transceiver 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 base station that corresponds to the selected collision detection code.

15. The baseband processor as in claim 14, wherein the controller causes the transceiver to transmit the power control signals to the base station following receipt of the corresponding collision detection code from the base station and subsequently causes the transceiver section to transmit the packet data.

16. A baseband processor for a wireless base station, the baseband processor comprising:

a spread-spectrum transceiver for transmitting and receiving wireless spread-spectrum signals;

a preamble processor, for detecting a preamble signal in a received spread-spectrum signal;

a data and control processor, for detecting and processing data and control information contained in a received spread-spectrum signal;

a packet formatter for formatting any one or more of data and control information into a packet for wireless transmission; and

a controller, responsive to the preamble processor and the data and control processor, for controlling the transceiver and the packet formatter, such that in operation the baseband processor;

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

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

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.

17. The baseband processor as in claim 16, wherein:

the reception of data from the remote station comprises receiving a coded collision detection signal;

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

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

18. The baseband processor as in claim 16, wherein the controller causes the baseband processor to broadcast a frame-timing signal over a common synchronization channel modulated with a common chip-sequence signal.

19. The baseband processor as in claim 18, wherein the controller detects reception of the access burst in one of a plurality of access slots defined in relation to the frame-timing signal.

20. The baseband processor as in claim 16, wherein:

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

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