Mobile communications system

• US 9,832,052 B2
• Filed: 02/12/2014
• Issued: 11/28/2017
• Est. Priority Date: 02/12/2013
• Status: Active Grant

• Current Assignee: Sepura Plc (Hytera Communications Corp. Ltd.)
• Original Assignee: Sepura Plc (Hytera Communications Corp. Ltd.)
• Inventors: Stephens, Peter, Nodar, Paul
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): Henson, Jamaal
• Application Number:
  US14/767,289
• Publication Number:
  US 20160006588A1
• Time in Patent Office: 1,385 Days
• Field of Search: None
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 5/22 using time-division multiplexing

Abstract

A modulation scheme for use in a digital mobile radio communications system. The modulation scheme uses a four slot time-division multiple access scheme with 12.5 kHz channels. Each 12.5 kHz channel contains plural sub-carriers and each sub-carrier is modulated with a modulation scheme that encodes at least 4 bits per symbol. The modulation scheme can be used in a standalone mobile radio communications system, or in a hybrid mobile radio communications system that also uses standard TETRA modulation schemes.

Claims

1. A method of operating a digital mobile radio communications system, comprising:

configuring a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol and that uses a fixed constant modulation level for data symbols, the four slot time division multiple access scheme further being configured to not include header symbols in uplink bursts in the scheme, for use for transmissions in the digital mobile radio communications system; and

configuring a device to use the four slot time-division multiple access scheme.

2. The method of claim 1, further comprising:

configuring a TETRA π

/4 DQPSK modulation scheme for use for transmissions in the digital mobile radio communications system; and

configuring the device to dynamically switch between the 12.5 kHz four slot time-division multiple access scheme and the TETRA π

/4 DQPSK modulation scheme for transmissions in the digital mobile radio communications system.

3. The method of claim 2, further comprising configuring the device to:

use the 12.5 kHz four slot time-division multiple access scheme for receiving transmissions and use the TETRA π

/4 DQPSK modulation scheme for sending transmissions in the digital mobile radio communications system;

or

use the 12.5 kHz four slot time-division multiple access scheme for sending transmissions and use the TETRA π

/4 DQPSK modulation scheme for receiving transmissions in the digital mobile radio communications system.

4. The method of claim 1, further comprising configuring the four slot time division multiple access scheme with four sub-carriers and 34 symbols per sub-carrier in each 12.5 kHz channel.

5. The method of claim 1, wherein the modulation scheme encodes 4 bits per symbol.

6. The method of claim 1, further comprising configuring the four slot time division multiple access scheme to use the higher level protocol layers, services and applications of the TETRA 1 standard.

7. The method of claim 1, wherein the protocol layers above the Lower MAC layer of the digital mobile radio communications system are the same as in the TETRA 1 standard.

8. A method of operating a digital mobile radio communications system, comprising:

configuring a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include pilot symbols only in the outer two sub-carriers of a 12.5 kHz channel, for use for transmissions in the digital mobile radio communications system; and

configuring a device to use the four slot time-division multiple access scheme.

9. A method of operating a digital mobile radio communications system, comprising:

configuring a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include relatively fewer synchronisation and pilot symbols in transmissions using the 12.5 kHz four slot time-division multiple access scheme than are included in transmissions using the TEDS standard, and being configured such that the ratio of synchronisation and pilot symbols to payload symbols is smaller in transmissions using the 12.5 kHz four slot time-division multiple access scheme than in transmissions using the TEDS standard, for use for transmissions in the digital mobile radio communications system; and

configuring a device to use the four slot time-division multiple access scheme.

10. A communications station for a digital mobile radio communications system, comprising:

a transmitter configured to use a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol and that uses a fixed constant modulation level for data symbols, the four slot time division multiple access scheme further being configured to not include header symbols in uplink bursts in the scheme, for transmissions in the digital mobile radio communications system.

11. The station of claim 10, wherein the transmitter is further configured to:

dynamically switch between making transmissions using the 12.5 kHz four slot time-division multiple access scheme and making transmissions using a TETRA π

/4 DQPSK modulation scheme.

12. The station of claim 11, wherein the station is configured:

to receive 12.5 kHz four slot time-division multiple access scheme transmissions and to send transmissions using the TETRA π

/4 DQPSK modulation scheme;

or

to receive TETRA π

/4 DQPSK transmissions and to send transmissions using the 12.5 kHz four slot time-division multiple access scheme.

13. The station of claim 10, wherein each 12.5 kHz channel comprises four sub-carriers with 34 symbols per sub-carrier.

14. The station of claim 10, wherein the modulation scheme encodes 4 bits per symbol.

15. The station of claim 10, wherein the higher level protocol layers, services and applications are the same as in the TETRA 1 standard.

16. The station of claim 10, wherein the protocol layers above the Lower MAC layer are the same as in the TETRA 1 standard.

17. A digital mobile radio communications system, comprising:

a transmitter configured to use a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol and that uses a fixed constant modulation level for data symbols, the four slot time division multiple access scheme further being configured to not include header symbols in uplink bursts in the scheme, for transmissions in the digital mobile radio communications system.

18. A communications station for a digital mobile radio communications system, comprising:

a transmitter configured to use a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include pilot symbols only in the outer two sub-carriers of a 12.5 kHz channel, for transmissions in the digital mobile radio communications system.

19. A communications station for a digital mobile radio communications system, comprising:

a transmitter configured to use a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include relatively fewer synchronisation and pilot symbols in transmissions using the 12.5 kHz four slot time-division multiple access scheme than are used in transmissions using the TEDS standard, and being configured such that the ratio of synchronisation and pilot symbols to payload symbols is smaller in transmissions using the 12.5 kHz four slot time-division multiple access scheme than in transmissions using the TEDS standard, for transmissions in the digital mobile radio communications system.

20. A non-transitory computer program element comprising computer software code portions which when run on a data processor performs a method of operating a digital mobile radio communications system, comprising:

configuring a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol and that uses a fixed constant modulation level for data symbols, the four slot time division multiple access scheme further being configured to not include header symbols in uplink bursts in the scheme, for use for transmissions in the system digital mobile radio communications; and

configuring a device to use the four slot time-division multiple access scheme.

21. A digital mobile radio communications system, comprising:

a transmitter configured to use a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include pilot symbols only in the outer two sub-carriers of a 12.5 kHz channel, for transmissions in the digital mobile radio communications system.

22. A digital mobile radio communications system, comprising:

a transmitter configured to use a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include relatively fewer synchronisation and pilot symbols in transmissions using the 12.5 kHz four slot time-division multiple access scheme than are used in transmissions using the TEDS standard, and being configured such that the ratio of synchronisation and pilot symbols to payload symbols is smaller in transmissions using the 12.5 kHz four slot time-division multiple access scheme than in transmissions using the TEDS standard, for transmissions in the digital mobile radio communications system.

23. A non-transitory computer program element comprising computer software code portions which when run on a data processor performs a method of operating a digital mobile radio communications system, comprising:

configuring a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of the 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include pilot symbols only in the outer two sub-carriers of a 12.5 kHz channel, for use for transmissions in the digital mobile radio communications system; and

configuring a device to use the four slot time-division multiple access scheme.

24. A non-transitory computer program element comprising computer software code portions which when run on a data processor performs a method of operating a digital mobile radio communications system, comprising:

configuring a four slot time-division multiple access scheme with a plurality of 12.5 kHz channels, with each of the plurality of 12.5 kHz channels containing a plurality of sub-carriers and each sub-carrier being modulated with a modulation scheme that encodes at least 4 bits per symbol, the four slot time division multiple access scheme further being configured to include relatively fewer synchronisation and pilot symbols in transmissions using the 12.5 kHz four slot time-division multiple access scheme than are included in transmissions using the TEDS standard, and being configured such that the ratio of synchronisation and pilot symbols to payload symbols is smaller in transmissions using the 12.5 kHz four slot time-division multiple access scheme than in transmissions using the TEDS standard, for use for transmissions in the digital mobile radio communications system; and

configuring a device to use the four slot time-division multiple access scheme.