Spread spectrum communication device and spread spectrum communication method

• US 20060203781A1
• Filed: 05/05/2006
• Published: 09/14/2006
• Est. Priority Date: 03/26/1998
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Murai, Hideshi, Yano, Yasuhiro
• Granted Patent: US 8,160,042 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• 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 communication method applied to a mobile communication system in a code division multiple access system for continuously transmitting frames in a normal mode and intermittently transmitting compressed frames in a compressed mode, in accordance with transmission power being controlled with a transmission power control step size, said method comprising:

at a base station, transmitting transmission power control information indicating increase or decrease of transmission power to a mobile station;

at a mobile station, receiving transmission power control information from the base station;

selecting one of a first transmission power control step size for the normal mode, and a second transmission power control step size for the compressed mode, the second transmission power control step size being greater than the first transmission power control step size;

adjusting transmission power with the transmission power control step size selected in the selecting step, based on the transmission power control information received in the receiving step;

performing interleaving on a frame in bit units in the normal mode and in the compressed mode, the frame being a unit of a transmission data stream; and

in the normal mode, transmitting the interleaved frame continuously in accordance with the transmission power adjusted in the adjusting step with the first transmission power control step size, and

in the compressed mode, compressing the interleaved frame, dividing the interleaved and compressed frame into a first portion including front edge of a frame timing and a second portion including rear edge of the frame window, the frame window being the same as a frame window in the normal mode, and transmitting the divided frame intermittently, in accordance with the transmission power adjusted in the adjusting step with the second transmission power control step size.

2. A communication method applied to a mobile communication system in a code division multiple access system for continuously transmitting frames in a normal mode and intermittently transmitting compressed frames in a compressed mode, in accordance with transmission power being controlled with a transmission power control step size, said method comprising:

at a mobile station, transmitting transmission power control information indicating increase or decrease of transmission power to a base station;

at a base station, receiving transmission power control information from the mobile station;

selecting one of a first transmission power control step size for the normal mode, and a second transmission power control step size for the compressed mode, the second transmission power control step size being greater than the first transmission power control step size;

adjusting transmission power with the transmission power control step size selected in the selecting step, based on the transmission power control information received in the receiving step;

performing interleaving on a frame in bit units in the normal mode and in the compressed mode, the frame being a unit of a transmission data stream; and

in the normal mode, transmitting the interleaved frame continuously in accordance with the transmission power adjusted in the adjusting step with the first transmission power control step size, and

in the compressed mode, compressing the interleaved frame, dividing the interleaved and compressed frame into a first portion including front edge of a frame timing and a second portion including rear edge of the frame window, the frame window being the same as a frame window in the normal mode, and transmitting the divided frame intermittently, in accordance with the transmission power adjusted in the adjusting step with the second transmission power control step size.

3. A communication method applied to a base station in a code division multiple access system for continuously transmitting frames in a normal mode and intermittently transmitting compressed frames in a compressed mode, in accordance with transmission power being controlled with a transmission power control step size, said method comprising:

receiving transmission power control information from a mobile station;

selecting one of a first transmission power control step size for the normal mode, and a second transmission power control step size for the compressed mode, the second transmission power control step size being greater than the first transmission power control step size;

adjusting transmission power with the transmission power control step size selected in the selecting step, based on the transmission power control information received in the receiving step;

performing interleaving on a frame in bit units in the normal mode and in the compressed mode, the frame being a unit of a transmission data stream; and

in the normal mode, transmitting the interleaved frame continuously in accordance with the transmission power adjusted in the adjusting step with the first transmission power control step size, and

in the compressed mode, compressing the interleaved frame, dividing the interleaved and compressed frame into a first portion including front edge of a frame timing and a second portion including rear edge of the frame window, the frame window being the same as a frame window in the normal mode, and transmitting the divided frame intermittently, in accordance with the transmission power adjusted in the adjusting step with the second transmission power control step size.