Spread spectrum communication device and spread spectrum communication method

• US 6,680,927 B2
• Filed: 12/21/2001
• Issued: 01/20/2004
• Est. Priority Date: 03/26/1998
• Status: Expired due to Term

• 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): Nguyen, Steven
• Assistant Examiner(s): PHAN, MAN U
• Application Number:
  US10/024,218
• Publication Number:
  US 20020054582A1
• Time in Patent Office: 760 Days
• Field of Search: 370/280, 370/335, 370/252, 370/342, 370/328, 370/331, 370/441, 370/479, 375/130, 375/224, 375/141, 375/142, 375/296, 375/262, 375/341, 714/790, 714/795, 714/792, 714/701, 714/755, 714/756
• 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 apparatus 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, comprising:

a memory unit configured to store a first transmission power control (TPC) step size for the normal mode and a second transmission power control (TPC) step size for the compressed mode, wherein the second transmission power control (TPC) step size is greater than the first transmission power control (TPC) step size; and

a transmission power control unit configured to adjust a transmission power level using one of said first and second transmission power control (TPC) step sizes based on a unit transmission power control (TPC) information received from a communication partner apparatus.

2. The spread spectrum communications apparatus according to claim 1, further comprising:

a compressing/transmitting unit configured to produce a compressed frame and to intermittently transmit the compressed frame across N (a natural number) slot units; and

a control unit configured to control said compressing/transmitting unit.

3. A spread spectrum communication apparatus 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, comprising:

a memory unit configured to store a first of transmission power control (TPC) step size for the normal mode and a plurality of second transmission power control (TPC) step sizes for the compressed mode, wherein at least one of the plurality of second transmission power control (TPC) step sizes is greater in magnitude than the first transmission power control (TPC) step size; and

a transmission power control unit configured to adjust a transmission power level using one of said first and second transmission power control (TPC) step sizes based on a unit of transmission power control information received from a communications partner apparatus.

4. The spread spectrum communications apparatus according to claim 3, further comprising:

a compressing/transmitting unit configured to produce a compressed frame and to intermittently transmit the compressed frame across N (a natural number) slot units; and

a control unit configured to control said compressing/transmitting unit.

5. A spread spectrum communication method applied in a code division multiple access system, comprising:

continuously transmitting uncompressed frames in a normal mode; and

intermittently transmitting compressed frames in a compressed mode, comprising,

receiving transmission power control (TPC) information representing a received power level from a communication partner apparatus,

accessing a table storing a first transmission power control (TPC) step size for the normal mode and a second transmission power control (TPC) step size for the compressed mode, with the second transmission power control (TPC) step size being greater than the first transmission power control (TPC) step size, and selecting one of the first and the second transmission power control (TPC) step size based on the transmission power control (TPC) information received in said receiving step, and

transmitting to said communication partner apparatus using said one of said first and second transmission power control (TPC) step sizes.

6. A spread spectrum communication method applied in a code division multiple access system, comprising:

continuously transmitting uncompressed frames in a normal mode; and

intermittently transmitting compressed frames in a compressed mode, comprising,

receiving transmission power control (TPC) information representing a received power level by a communication partner apparatus,

accessing a table storing a first transmission power control (TPC) step size for the normal mode and a plurality of second transmission power control (TPC) step sizes for the compressed mode, with one of the plurality of second transmission power control (TPC) step sizes being greater than the first transmission power control (TPC) step size, and

selecting one of the first and second transmission power control (TPC) step sizes based on transmission power control (TPC) information received in said receiving step, and

transmitting to said communication partner apparatus using the one of the first and second step sizes of transmission power control (TPC).

7. A spread spectrum communication method applied in a code division multiple access system, comprising:

transmitting uncompressed frames; and

transmitting compressed frames, comprising,

receiving transmission power control (TPC) information representing a received power level from a communication partner apparatus,

accessing a table storing a first transmission power control (TPC) step size for a normal mode and a second transmission power control (TPC) step size for a compressed mode, with the second transmission power control (TPC) step size being greater than the first transmission power control (TPC) step size; and

selecting one of the first and the second transmission power control (TPC) step size based on the transmission power control (TPC) information received in said receiving step, and

transmitting to said communication partner apparatus using the one of the first and the second transmission power control (TPC) step size.

8. A spread spectrum communication method applied in a code division multiple access system, comprising:

transmitting uncompressed frames; and

transmitting compressed frames, comprising,

receiving transmission power control (TPC) information representing a received power level from a communication partner apparatus,

accessing a table storing a first transmission power control (TPC) step size for a normal mode and a plurality of second transmission power control (TPC) step size for a compressed mode, with at least one of the plurality of second transmission power control (TPC) step size being greater than the first transmission power control (TPC) step size, and

selecting one of the first and the second transmission power control (TPC) step size based on transmission power control (TPC) information received in said receiving step, and

transmitting to said communication partner apparatus using said one of said first and second transmission power control (TPC) step sizes.

9. A spread spectrum communication method applied in a code division multiple access system transmitting uncompressed frames and compressed frames, wherein the compressed frame has a transmission gap, comprising;

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

adjusting transmission power with the selected transmission power control step size based on transmission power control information received from a communication partner; and

transmitting the uncompressed frames and the compressed frames in accordance with the adjusted transmission power.

10. The method according to claim 9, further comprising:

receiving the transmission power control information indicating an increase or a decrease in power.

11. The method according to claim 10, wherein the uncompressed frames are continuously transmitted in the normal mode, and the compressed frames are intermittently transmitted in the compressed mode in the step of transmitting.

12. A spread spectrum communication apparatus applied in a code division multiple access system transmitting an uncompressed frame and a compressed frame, wherein the compressed frame has a transmission gap, comprising:

a receiver for receiving transmission power control information indicating an increase or a decrease in power from a communication partner apparatus;

a controller for controlling transmission power on the uncompressed and the compressed frames in accordance with the transmission power control information, by increasing or decreasing current power with a plurality of power control step sizes, wherein the power control step size is increased in a period after the transmission gap in the compressed frame; and

a transmitter for transmitting the uncompressed and the compressed frames with the adjusted transmission power, the adjusted transmission power changing over the uncompressed and compressed frames.

13. The spread spectrum communication apparatus according to claim 12, wherein the power control step sizes include 1 dB and 3 dB.