Dual mode satellite/cellular terminal

• US 5,959,984 A
• Filed: 12/22/1997
• Issued: 09/28/1999
• Est. Priority Date: 07/23/1997
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Dent, Paul W.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US08/996,153
• Time in Patent Office: 645 Days
• Field of Search: 370/347, 370/330, 370/336, 370/337, 370/342, 370/346, 370/420, 370/479, 370/465, 370/294, 455/12.1, 455/13.3, 455/15, 455/20, 455/25, 455/67.6, 455/77, 455/452, 455/453, 455/434, 455/450
• US Class Current: 370/347
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• 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 dual-mode mobile communications unit comprising:

means for communicating voice or data traffic using Time Division Multiple Access (TDMA) signal bursts during allocated timeslots of repetitive TDMA frames, wherein said voice or data traffic is communicated to a land-based network station at a first data rate during a first plurality of timeslots, and wherein said voice or data traffic is communicated to an orbiting relay station at a second data rate during a second plurality of timeslots, with said second plurality of time slots being lower than said first plurality of time slots.

2. 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.

3. A communications system for providing a communications service to a plurality of first stations with the aid of a network of relay stations each of said relay stations, comprising:

coding means for coding data for transmission to said first stations to produce signal bursts;

TDMA burst transmission means for relaying said signal bursts to each of said first stations using respective timeslots of a repetitive TDMA frame period such that each of said first stations receives signal bursts in its respective timeslot;

detection means for detecting when no data is temporarily required to be sent to one of said first stations; and

means controlled by said detection means to transmit signal bursts intended for another of said first stations in the timeslot designated for said one of said first stations temporarily receiving no data as well as transmitting signal bursts in said another station'"'"'s designated timeslot.

4. A dual-mode satellite/cellular radio telephone system using a TDMA format, comprising mobile stations, at least a cellular network station and at least a satellite relay station for transmitting TDMA signal bursts including the method of:

transmitting bursts in said TDMA format intended for a specific mobile station at a first repetition rate from said cellular network station alternatively at a second repetition rate being a sub-multiple of said first repetition rate from said satellite relay station;

dividing bursts transmitted at said first repetition rate into superframe groups each comprising traffic bursts, a Slow Associated Control Channel burst and an idle frame not containing a transmitted information burst; and

using said idle frame at said specific mobile station to change its TDMA burst receiver channel frequency to that of a neighboring cellular network station or to the channel frequency of said satellite relay station and performing a signal analysis on the signal received on that channel frequency.

5. The method according to claim 4, further comprising the step of:

reporting from said specific mobile station to said cellular network station the results of said signal analysis.

6. The method according to claim 4, wherein said method further includes communicating channel frequencies of said neighboring cellular network station and frequencies of said satellite relay station from said cellular network station to said specific mobile station.

7. The method according to claim 5, wherein said reported signal analysis are used at said network station to determine when said mobile station shall be switched to receive data from a satellite relay station instead of one of said network stations.