Spread spectrum communication device and spread spectrum communication method

• US 7,525,945 B2
• Filed: 02/09/2007
• Issued: 04/28/2009
• 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:
  US11/673,396
• Publication Number:
  US 20070129095A1
• Time in Patent Office: 809 Days
• Field of Search: 370241-252, 370311-342, 370345-347, 455 67- 69, 455517-522, 375130-148, 375227-240
• 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 communication method applied to a mobile communication system in a code division multiple access system for continuously transmitting uncompressed 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 to a mobile station, the power control information instructing increase or decrease of transmission power; and

at the mobile station,

receiving the transmission power control information from the base station; and

adjusting the transmission power for the normal mode and the compressed mode with the transmission power control step size based on the transmission power control information, wherein,

the adjusting step includes

first adjusting for adjusting the transmission power with a first transmission power control step size for the normal mode, and

second adjusting for adjusting the transmission power with a plurality of transmission power control step sizes that include a second transmission power control step size larger than the first transmission power control step size for the compressed mode;

in the normal mode,

transmitting the uncompressed frame including a predetermined number of slots continuously in accordance with the transmission power adjusted in the first adjusting step, and

in the compressed mode,

compressing the frame,

dividing the compressed frame into a first portion including front edge of a frame window and a second portion including rear edge of the frame window to set an idle period, whose length can be expressed by number of slot, between the first portion and the second portion, the frame window being the same as a frame window in the normal mode, and

transmitting the divided compressed frame intermittently, in accordance with the transmission power adjusted in the second adjusting step.

2. The communication method according to claim 1, wherein the adjusting step includes:

first adjusting step for adjusting the transmission power with the first transmission power control step size for the uncompressed frames, and

second adjusting step for adjusting the transmission power with the first transmission power control step size and the second transmission power control step size for the compressed frames.

3. A communication method applied to a base station in a code division multiple access system for continuously transmitting uncompressed 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, the power control information instructing increase or decrease of transmission power; and

adjusting the transmission power for the uncompressed frames and the compressed frames with the transmission power control step size based on the transmission power control information, wherein the adjusting step includes;

adjusting the transmission power with a first transmission power control step size for the uncompressed frames, and

adjusting the transmission power with a plurality of transmission power control step sizes that include a second transmission power control step size larger than the first transmission power control step size for the compressed frames.

4. The communication method according to claim 3, wherein the adjusting step further includes:

adjusting the transmission power with the first transmission power control step size for the uncompressed frames, and

adjusting the transmission power with the first transmission power control step size and the second transmission power control step size for the compressed frames.