Spread spectrum communication device and spread spectrum communication method

• US 7,995,550 B2
• Filed: 10/31/2007
• Issued: 08/09/2011
• Est. Priority Date: 03/26/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Murai, Hideshi, Yano, Yasuhiro
• Primary Examiner(s): PHAN, MAN U
• Application Number:
  US11/979,218
• Publication Number:
  US 20080062952A1
• Time in Patent Office: 1,378 Days
• Field of Search: 370241-252, 370331-335, 370342-347, 370468-470, 455 67- 69, 455517-522
• US Class Current: 370/342
• CPC Class Codes: G08C 15/00 Arrangements characterised by the use of multiplexing for the transmission of a plurality of signals over a common path
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/70735 Code identification H04B1/7083 takes precedence
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/7083 Cell search, e.g. using a three-step approach
• CPC Class Codes: H04B 1/7087 Carrier synchronisation aspects
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• 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 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0083 : Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04W 36/0088 : Scheduling hand-off measurements
• CPC Class Codes: H04W 36/302 : due to low signal strength
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/267 : taking into account the information rate
• CPC Class Codes: H04W 52/28 : using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
• CPC Class Codes: H04W 52/287 : when the channel is in stand-by
• CPC Class Codes: H04W 52/288 : taking into account the usage mode, e.g. hands-free, data transmission, telephone
• 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 52/362 : Aspects of the step size
• CPC Class Codes: H04W 52/367 : Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/44 : in connection with interruption of transmission
• CPC Class Codes: H04W 52/48 : during retransmission after error or non-acknowledgment
• CPC Class Codes: H04W 52/56 : Detection of errors of TPC bits
• CPC Class Codes: H04W 52/60 : using different transmission rates for TPC commands
• CPC Class Codes: H04W 56/00 : Synchronisation arrangements

Abstract

In a compressed mode, a spread spectrum communication device interleaves bit units across multiple frames using an interleaver, reduces the spreading factor using a framing/spreading unit, outputs the compressed mode frames at a predetermined compressed mode frame timing, and increases the average transmission power in the compressed mode at a radio frequency transmitter. Furthermore, a handover between different frequencies is carried out by establishing synchronization to another frequency carrier, based on a first search code and a second search code which have been detected, and moreover, a handover between different communication systems is carried out by establishing synchronization to a GSM, based on an FCCH and a SCH which have been detected.

Claims

1. A spread spectrum communication method applied to a mobile station in a code division multiple access system continuously transmitting uncompressed frames in a normal mode, and intermittently transmitting compressed frames in a compressed mode, the method comprising:

receiving a compressed downlink frame in the compressed mode and transmission power control information transmitted from a base station,

the compressed downlink frame being provided, at a base station, with an idle period formed

by compressing an interleaved downlink frame interleaved in bit units,

by dividing the compressed downlink frame into a front portion and a rear portion, and

by arranging the front portion and the rear portion such that the front portion includes a front edge of a frame window and that the rear portion includes a rear edge of the frame window, and

the transmission power control information indicating an increase or a decrease in uplink transmission power;

monitoring a frequency component of another frequency carrier during the idle period of the compressed downlink frame received;

generating a compressed uplink frame by compressing an uplink frame in the compressed mode; and

adjusting uplink transmission power on the uncompressed uplink frames in normal mode and compressed uplink frames in compressed mode in accordance with the transmission power control information, by increasing or decreasing current uplink transmission power with variable power control step size for the normal mode and with variable power control step size for the compressed mode.

2. The spread spectrum communication method according to claim 1, wherein the mobile station adjusts uplink transmission power on the uncompressed uplink frames in normal mode and compressed uplink frames in compressed mode in accordance with the transmission power control information, by increasing or decreasing current uplink transmission power with power control step size which can be set to one of a plurality of values for the normal mode and with power control step size which can be set to one of a plurality of values for the compressed mode.

3. A spread spectrum communication method applied to a code division multiple access system continuously transmitting uncompressed frames in a normal mode, and intermittently transmitting compressed frames in a compressed mode, the method comprising:

at a base station,

first interleaving step of performing interleaving on a downlink frame in bit units;

first compressing step of compressing the downlink frame after interleaving to generate a compressed downlink frame, in compressed mode;

transmitting, to a mobile station, a compressed downlink frame provided with an idle period, and transmission power control information, the idle period being formed by dividing the compressed downlink frame into a front portion and a rear portion, and by arranging the front portion and the rear portion such that the front portion includes a front edge of a frame window and that the rear portion includes a rear edge of the frame window, the transmission power control information indicating an increase or a decrease in transmission power; and

at the mobile station,

receiving a compressed downlink frame and transmission power control information, transmitted from the base station;

monitoring a frequency component of another frequency carrier during the idle period of the compressed downlink frame;

second interleaving step of performing interleaving on an uplink frame in bit units;

a second compressing step of generating a compressed uplink frame by compressing the interleaved uplink frame in the compressed mode; and

adjusting transmission power on an uplink uncompressed frames in normal mode and the uplink compressed frames in compressed mode in accordance with the transmission power control information, by increasing or decreasing current transmission power with variable power control step size for the normal mode and with variable power control step size for the compressed mode.

4. The spread spectrum communication method according to claim 3, wherein the mobile station adjusts transmission power on the uplink uncompressed frames in normal mode and the uplink compressed frames in compressed mode in accordance with the transmission power control information, by increasing or decreasing current transmission power with power control step size which can be set to one of a plurality of values for the normal mode and with power control step size which can be set to one of a plurality of values for the compressed mode.

5. A spread spectrum communication method applied to a base station in a code division multiple access system continuously transmitting uncompressed frames in a normal mode, and intermittently transmitting compressed frames in a compressed mode, wherein the base station includes,

an interleaving unit configured to perform interleaving on a downlink frame in bit units,

a compressing unit configured to compress the interleaved downlink frame to generate a compressed downlink frame, in compressed mode,

a transmitting unit configured to transmit an uncompressed downlink frame and the compressed downlink frame,

a receiving unit configured to receive transmission power control information, transmitted from the mobile station, indicating increase or decrease in downlink transmission power, and

a control unit configured to control the compressing unit and the transmitting unit, the method comprising:

controlling step of controlling the compressing unit and the transmitting unit by the control unit so as to

provide the compressed downlink frame with an idle period by dividing the compressed downlink frame into a front portion and a rear portion, and by arranging the front portion and the rear portion such that the front portion includes a front edge of a frame window and that the rear portion includes a rear edge of the frame window,

adjust the transmission power on the uncompressed frames in normal mode and compressed frames in compressed mode in accordance with the transmission power control information, by increasing or decreasing current transmission power with variable power control step size for the normal mode and with variable power control step size for the compressed mode, and

transmit the uncompressed downlink frame and the compressed downlink frame to a mobile station by the downlink transmission power adjusted.

6. The spread spectrum communication method according to claim 5, wherein the base station adjusts transmission power on the uncompressed frames in normal mode and compressed frames in compressed mode in accordance with the transmission power control information, by increasing or decreasing current transmission power with power control step size which can be set to one of a plurality of values for the normal mode and with power control step size which can be set to one of a plurality of values for the compressed mode.