Data communication system

• US 5,598,416 A
• Filed: 02/10/1995
• Issued: 01/28/1997
• Est. Priority Date: 02/18/1994
• Status: Expired due to Term

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamada, Daisuke, Kato, Osamu
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Patel, Ajit
• Application Number:
  US08/386,463
• Time in Patent Office: 718 Days
• Field of Search: 370/95.1, 370/95.3, 370/85.7, 370/84, 370/18, 379/0.59, 379/34, 379/60, 455/33.1, 455/33.2, 455/54.1, 455/54.2, 375/200, 375/205
• US Class Current: 370/468
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04L 5/1446 of transmission speed
• CPC Class Codes: H04W 28/22 Negotiating communication rate

Abstract

In case the number of usable channels is insufficient when a data communication system transmits information by using a plurality of channels, an information transmission rate reduction detector circuit included in a terminal interface circuit requests a terminal to reduce an information transmission rate and thereby reduce the probability of call blockage of the terminal. Also, in case the number of usable channels is insufficient at the time of hand over, hand over failure of the data communication system is reduced by lowering the information transmission rate of the terminal.

Claims

1. A data communication system provided between a base station and a terminal, said data communication system receiving transmission data from said terminal and transmitting said transmission data to said base station through at least one usable channel in a plurality of channels, said data communication system comprising:

(a) a terminal interface which comprises;

(i) means for determining whether a number of usable channels included in said at least one usable channel is sufficient for transmission of the transmission data at one of a first information transmission rate and a first source encoding rate;

(ii) means for requesting said terminal to reduce an information transmission rate, at which said transmission data is transmitted, from said first information transmission rate to a second information transmission rate when the means for determining determines that the number of usable channels is insufficient for transmission at said first information transmission rate and for requesting said terminal to reduce a source encoding rate, with which said transmission data is generated, from said first source encoding rate to a second source encoding rate when said means for determining determines that the number of usable channels is insufficient for transmission at said first source encoding rate;

(b) a received data converter circuit for receiving from said base station a first signal including a control signal indicating said number of usable channels;

(c) timing control means for receiving from said terminal a second signal indicating a number of said plurality of channels which said terminal desires to use for transmitting said transmission data and for generating a transmission control signal which indicates said number of channels which said terminal desires to use;

(d) said received data converter circuit providing said control signal to said timing control means, said timing control means detecting said number of usable channels from said control signal and informing said means for determining of said number of usable channels; and

(e) a transmission data converter circuit for adding said transmission control signal received from said timing control means to the transmission data received from said terminal for transmission to said base station.

2. A data communication system according to claim 1, wherein said received data converter circuit takes out said control signal from said first signal.

3. A data communication system provided between a base station and a terminal, said data communication system receiving transmission data from said terminal and transmitting said transmission data to said base station through at least one usable channel in a plurality of channels, said data communication system comprising:

(a) a terminal interface which comprises;

(i) means for determining whether a number of usable channels included in said at least one usable channel is sufficient for transmission of the transmission data at one of a first information transmission rate and a first source encoding rate;

(ii) means for requesting said terminal to reduce an information transmission rate, at which said transmission data is transmitted, from said first information transmission rate to a second information transmission rate when the means for determining determines that the number of usable channels is insufficient for transmission at said first information transmission rate and for requesting said terminal to reduce a source encoding rate, with which said transmission data is generated, from said first source encoding rate to a second source encoding rate when said means for determining determines that the number of usable channels is insufficient for transmission at said first source encoding rate, wherein said transmission data are transmitted in accordance with a time division multiple access operation in which an amount of information transmitted in any one of said plurality of channels is transmitted in accordance with a number of unit slots assigned to said any one of said plurality of channels.

4. A data communication system provided between a base station and a terminal, said data communication system receiving transmission data from said terminal and transmitting said transmission data to said base station through at least one usable channel in a plurality of channels, said data communication system comprising:

(a) a terminal interface which comprises;

(i) means for determining whether a number of usable channels included in said at least one usable channel is sufficient for transmission of the transmission data at one of a first information transmission rate and a first source encoding rate;

(ii) means for requesting said terminal to reduce an information transmission rate, at which said transmission data is transmitted, from said first information transmission rate to a second information transmission rate when the means for determining determines that the number of usable channels is insufficient for transmission at said first information transmission rate and for requesting said terminal to reduce a source encoding rate, with which said transmission data is generated, from said first source encoding rate to a second source encoding rate when said means for determining determines that the number of usable channels is insufficient for transmission at said first source encoding rate, wherein said transmission data are transmitted in accordance with a code division multiple access operation through said at least one usable channel after being spread over said at least one usable channel by way of spreading codes which are assigned to each channel of said at least one usable channel.

5. A data communication system provided between a base station and a terminal, said data communication system receiving transmission data from said terminal and transmitting said transmission data to said base station through at least one usable channel in a plurality of channels, said data communication system comprising a terminal interface which comprises:

means for receiving from said terminal one of a first number indicating a number of channels desired to be used for transmitting said transmission data at one of a first information transmission rate and a first source encoding rate and a second number indicating a number of channels to be needed at a time of hand over and for receiving from said base station a third number indicating a number of usable channels included in said at least one usable channel; and

an information transmission rate reduction detector means for comparing said one of said first number and said second number with said third number and for requesting said terminal to reduce one of (a) an information transmission rate from said first information transmission rate to a second rate information transmission when said third number represents a number of usable channels that is insufficient for transmission or said hand over at said first information transmission rate and (b) a source encoding rate from said first source encoding rate to a second source encoding rate when said third number represents a number of usable channels that is insufficient for transmission or said hand over at said first source encoding rate.

6. A data communication system according to claim 5, wherein;

said terminal comprises a video terminal;

said transmission data comprise image data; and

said information transmission rate reduction detector circuit requests said video terminal to reduce said source encoding rate when said information transmission rate reduction detector circuit determines that said number of usable channels is insufficient.

7. A data communication system according to claim 5, wherein:

(a) said means for receiving comprises a received data converter circuit for receiving from said base station a first signal including a control signal indicating said third number indicating said number of usable channels;

(b) said information transmission rate reduction circuit comprises timing control means for receiving from said terminal a second signal indicating said first number indicating said number of channels desired to be used for transmitting said transmission data and for generating a transmission control signal which indicates said first number indicating said number of channels desired to be used;

(c) said received data converter circuit providing said control signal to said timing control means, said timing control means detecting said number of usable channels from said control signal; and

(d) a transmission data converter circuit for adding said transmission control signal received from said timing control means to the transmission data received from said terminal for transmission to said base station.

8. A data communication system according to claim 7, wherein said received data converter circuit takes out said control signal from said first signal.

9. A data communication system according to claim 5, wherein said transmission data are transmitted in accordance with a time division multiple access operation in which an amount of information transmitted in any one of said plurality of channels is transmitted in accordance with a number of unit slots assigned to said any one of said plurality of channels.

10. A data communication system according to claim 5, wherein said transmission data are transmitted in accordance with a code division multiple access operation through said at least one usable channel after being spread over said at least one usable channel by way of spreading codes which are assigned to each channel of said at least one usable channel.