Dual mode satellite/cellular terminal

• US 5,663,957 A
• Filed: 07/12/1995
• Issued: 09/02/1997
• Est. Priority Date: 07/12/1995
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Dent, Paul W.
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US08/501,575
• Time in Patent Office: 783 Days
• Field of Search: 371/5.4, 371/5.5, 371/32, 371/33, 371/43, 371/46, 371/67.1, 371/68.2, 375/260, 375/267, 375/285, 375/347, 370/294, 370/337, 370/345, 370/347, 370/348, 370/350, 370/442, 370/443, 370/468, 370/536, 370/915
• US Class Current: 370/347
• CPC Class Codes: H04B 1/408 the transmitter oscillator frequency being identical to the receiver local oscillator frequency
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• 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 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04W 52/06 TPC algorithms
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• 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 52/30 using constraints in the total amount of available transmission power
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A method and apparatus of communicating information using Time Division Multiple Access and adaptive transmission and reception are disclosed. Signal bursts are transmitted from TDMA transmitters to a TDMA receiver wherein the transmitter codes the information and transmits coded information to the receiver using at least one of two timeslots of a plurality of timeslots in a repetitive TDMA frame period. Both of the two timeslots are received whether or not the transmitter has transmitted using one or two timeslots and the received signals are classified as intended and non-intended. Successively received signals classified as intended are then assembled into a block for decoding to reproduce the information.

Claims

1. A method of communicating information using Time Division Multiple Access and adaptive transmission and reception, comprising the steps of:

transmitting signal bursts from TDMA transmission means to a TDMA receiving means wherein said transmission means codes said information and transmits coded information to said receiving means using at least one of two timeslots of a plurality of timeslots in a repetitive TDMA frame period;

receiving both of said two timeslots whether or not said transmitting means has transmitted using said one or said two timeslots and classifying received signals as intended and non-intended;

assembling successively received signals classified as intended into a block for decoding;

decoding said block to reproduce said information.

2. A method of communicating information according to claim 1 wherein said transmission means codes said information using a convolutional code.

3. A method of communicating information according to claim 1 wherein said transmission means inserts a known symbol pattern into said coded information for transmission.

4. A method of communicating information according to claim 3 wherein said receiving means classifies said received signals as intended and not intended based upon detection of said known pattern.

5. A method of communicating information according to claim 1, wherein said burst transmission means uses said two time slots when determined to be required by said TDMA receiving means in order to obtain good decoded information quality and said burst transmission means uses one time slot when it is determined that one timeslot provides a good decoded information quality.

6. A method of communicating information according to claim 1, wherein said burst transmitter means when using said two timeslots repeats in a second of said two timeslots transmissions of coded symbols already transmitted in a first of said two timeslots.

7. A method of communicating information according to claim 1, wherein said burst transmitter means when using said two timeslots transmits in the second of said two timeslots at least some information symbols coded in a second manner that were already transmitted in the first of said two timeslots coded in a first manner.

8. A method of communicating information according to claim 7, wherein said first manner of coding comprises selecting half of the output bits of an error correction coder when the input bits to said coder are said at least some information symbols and said second manner of coding comprises selecting the other half of said output bits.

9. A method of communicating information according to claim 1, wherein said TDMA burst transmission means when using said two timeslot transmission comprises a first TDMA transmission means for transmitting on the first of said two timeslots and a second, separate TDMA transmission means for transmitting on the second of said two timeslots.

10. A method of communicating information according to claim 9, wherein said first and second TDMA transmission means are not co-located.

11. A method of communicating information according to claim 10, wherein said first and second TDMA transmission means comprise different cellular base stations and sites.

12. A method of communicating information according to claim 9, wherein said first and second TDMA transmission means respectively comprise a first and a second orbiting satellite relay station.

13. A method of communicating information according to claim 9, wherein said first and second TDMA transmission means respectively comprise a first and a second airborne relay station.

14. A method of communicating information according to claim 9, wherein said first and second TDMA transmission means respectively comprise a first and a second cellular base station transmitter.

15. A method of communicating information according to claim 14, wherein said first and second cellular base station transmitter are connected to separate sector inputs of a sectorized transmit antenna.

16. A method of communicating information according to claim 9, wherein said two timeslot transmission is employed when said TDMA burst receiving means is located in a handover regime between said first and second TDMA burst transmission means.

17. A TDMA communications apparatus providing an improved transmit and receive diversity operation, comprising:

coding means for coding an information bitstream such that for every information bit input to said coder a plurality of coded output bits are generated;

first TDMA burst transmission means for transmitting half of said plurality of coded bits using a first TDMA timeslot of a repetitive frame period and a first sequence of radio channel frequencies;

second TDMA burst transmission means for conditionally transmitting the other half of said plurality of coded bits using a second timeslot of a repetitive frame period and a second sequence of radio channel frequencies;

TDMA receiving means for receiving on said first timeslot on a frequency in said first frequency series alternately with receiving on said second timeslot on a frequency in said second series and producing demodulated output signals to a decoder; and

decoding means for classifying said output signals received respectively in said first and said second timeslots as intended and non-intended and decoding signals classified as intended to reproduce said information bitstream.

18. The TDMA communications apparatus according to claim 17, wherein said conditional transmission by said second TDMA burst transmission means is based on the signal quality decoded by said TDMA receiving means.

19. A portable satellite communications terminal using time division multiple access, comprising:

TDMA burst receiving means for receiving and analyzing signal bursts received in a receive timeslot of a repetitive TDMA frame period and producing decoded information and a signal quality indication;

TDMA burst transmitting means for coding information and said signal quality indication to produce coded signal bursts for transmission and transmitting said coded bursts in an allocated transmit timeslot of even-numbered TDMA frames and conditionally transmitting coded bursts in an allocated timeslot of odd-numbered TDMA frames in dependence on said signal quality indication.

20. A portable satellite communications terminal using time division multiple access comprising:

TDMA burst receiving means for receiving and analyzing signal bursts received in a receive timeslot of a repetitive TDMA frame period and producing decoded information containing mode commands; and

TDMA burst transmitting means for coding information and said signal quality indication to produce coded signal bursts for transmission and transmitting coded bursts in an allocated transmit timeslot of even-numbered TDMA frames and conditionally transmitting coded bursts in an allocated timeslot of odd-numbered TDMA flames in dependence on said mode commands.

21. A portable satellite terminal according to claim 20, further comprising:

means for changing the radio channel frequency of said TDMA burst receiving means between successive TDMA frames.

22. A portable satellite terminal according to claim 20, further comprising:

means for changing the radio channel frequency of said TDMA burst transmission means between said even and odd-numbered frames.

23. A portable satellite terminal according to claim 20, further comprising:

means for maintaining timing synchronization of said TDMA burst receiving means independently for receiving signal bursts in respectively even and odd-numbered frames.

24. A portable satellite communications terminal using time division multiple access, comprising:

TDMA burst receiving means synchronized by synchronizing means to receive and analyze signal bursts received in allocated receive timeslots of a repetitive TDMA frame period and to produce decoded information and a signal quality indication;

synchronizing means for synchronizing said TDMA burst receiving means independently for even-numbered and odd-numbered ones of said TDMA frame periods; and

TDMA burst transmitting means for coding information and said signal quality indication to produce coded signal bursts for transmission and transmitting coded bursts in allocated transmit timeslots in said repetitive TDMA frame period.