Spread spectrum communication device and spread spectrum communication method

• US 20030137958A1
• Filed: 03/06/2003
• Published: 07/24/2003
• 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 7,286,518 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 spread spectrum communication device applied in a code division multiple access system for continuously transmitting frames in a normal mode, and intermittently transmitting compressed frames in a compressed mode, said device comprising:

a compressing/intermittent transmitting unit configured to compress an uncompressed frame into a compressed frame and intermittently transmit the compressed frame; and

a control unit configured to control said compressing/intermittent transmitting unit so that said compressing/intermittent transmitting unit intermittently transmits the compressed frame at a transmission rate lower than a normal mode transmission rate and with a transmission power equal to a normal mode transmission power.

2. The spread spectrum communication device according to claim 1, further comprising:

an interleaving unit configured to interleave in bit units the uncompressed frame, or the compressed frame so as to reduce an effect of transmission errors; and

said control unit configured to control said interleaving unit so that, in the compressed mode, interleaving is performed across multiple frames.

3. The spread spectrum communication device according to claim 1, comprising:

said control unit configured to control said compressing/intermittent transmitting unit so as to divide the compressed frame into a front portion and a rear portion of a normal mode frame timing.

4. The spread spectrum communication device according to claim 1, comprising:

said control unit configured to control said compressing/intermittent transmitting unit so as to slot said compressed frame into a slotted frame, and intermittently transmit the slotted frame in N (a natural number) slot units.

5. A spread spectrum communication method applied in a code division multiple access system for continuously transmitting frames in a normal mode, and intermittently transmitting compressed frames in a compressed mode, said method comprising:

dividing a frame, which is a unit of a transmission data stream, into multiple slots in the compressed mode; and

intermittently transmitting in N (N=a natural number) slot units the frame divided in said dividing step.

6. A spread spectrum communication method applied in a code division multiple access system for continuously transmitting frames, a frame being a unit of transmission data, in a normal mode and intermittently transmitting compressed frames in a compressed mode, said method comprising:

interleaving in bit units at least one of a plurality of frames in order to reduce an effect of transmission errors; and

using code-multiplexing to compress, in a given frame timing, the at least one of a plurality of frames interleaved in bit units in said interleaving step, and outputting the at least one of a plurality of frames intermittently.

7. A spread spectrum communication method applied in a code division multiple access system for continuously transmitting frames in a normal mode, and intermittently transmitting compressed frames in a compressed mode, said method comprising:

using code-multiplexing to compress, in a given frame timing, multiple frames and output them intermittently; and

interleaving the compressed frames in bit units.

8. A spread spectrum communication method applied in a code division multiple access system for continuously transmitting frames, a frame being a unit of transmission data, in a normal mode and intermittently transmitting compressed frames in a compressed mode, said method comprising:

compressing a frame in the compressed mode; and

using the same transmission power as in the normal mode to transmit intermittently the frame compressed in said compressing step at a lower transmission rate than in the normal mode.