Method of adapting the air interface in a mobile radio system and corresponding base transceiver station, mobile station and transmission mode

• US 6,456,598 B1
• Filed: 08/03/2000
• Issued: 09/24/2002
• Est. Priority Date: 04/13/1994
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent France, SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent France, SA (Nokia Corporation)
• Inventors: Le Strat, Evelyne, Delprat, Marc
• Primary Examiner(s): NGO, RICKY QUOC
• Application Number:
  US09/631,379
• Time in Patent Office: 782 Days
• Field of Search: 370/252, 370/253, 370/328, 370/329, 370/331, 370/332, 370/333, 370/468, 370/337, 370/347, 370/442, 370/465, 370/466, 455/436, 455/63, 455/69, 455/500, 455/501, 455/502, 455/517, 455/67.1, 455/67.3
• US Class Current: 370/252
• CPC Class Codes: H04B 17/20 of receivers
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0014 by adapting the source coding
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• 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 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

A mobile radio system enables exchange of bidirectional digital signals between at least one mobile station and at least one base transceiver station and provides at least two coding modes, each mode corresponding to a predetermined source code and a predetermined channel code for the transmission of a wanted signal for each transmission direction. Each source code corresponds to a given user bit rate and each channel code corresponds to a given coding efficiency and therefore to a given total bit rate for a given source code. For adaptation of the air interface of this system, at the time of a call between a mobile station and a base transceiver station, two separate analyses of transmission quality are carried out for each transmission direction, respectively, and, for each transmission direction, one of the coding modes is selected in accordance with the corresponding transmission quality analysis.

Claims

1. A method for exchanging digital signals bi-directionally between at least one mobile station and a network entity in a mobile radio system providing at least two coding modes, each mode corresponding to a predetermined source coding and a predetermined channel coding for transmission of a wanted signal for each transmission direction, said method comprising the steps of:

at the time of a call between a mobile station and the network entity, carrying out two separate measurements of transmission quality for each transmission direction, respectively; and

for each transmission direction, selecting, in said network entity, one of said coding modes in accordance with a corresponding one of said two transmission quality measurements;

wherein said step of selecting a coding mode includes the step of comparing information representative of a measured transmission quality with at least one predetermined threshold which is a predetermined value of a signal to interference ratio.

2. The method claimed in claim 1, wherein there are two sets of at least one threshold, the first set being used in the comparing step if the measured transmission quality deteriorates, and the second set being used if the measured transmission quality improves.

3. The method claimed in claim 1, when the transmission quality measurement for each transmission direction comprises determining at least one of the following:

the bit error rate of the received signal,

the power of the received signal

the distance between the mobile station and the network entity,

an estimate of the impulse response of the transmission channel,

the time alignment

the signal to noise ratio,

the signal to interference ratio, and

the traffic load.

4. The method claimed in claim 1, wherein said coding mode selection also allows for at least one of the following:

a required quality level for said call,

a required quality level for at least one transmission direction and for said call,

a type of service carried by said call, and

traffic load.

5. The method claimed in claim 2, wherein a coding mode is selected in such a manner as to limit the quantity of resource allocated in each transmission direction and/or to optimize quality.

18. The method according to claim 1, wherein said selecting step includes selecting a source coding and a channel coding.

21. The method as claimed in claim 1, wherein said network entity is a base transceiver station.

6. A mobile radio system including at least one mobile station and a network entity capable of bi-directionally exchanging digital signals between at least one mobile station and the network entity, said system comprising:

means for providing at least two coding modes, each mode corresponding to a predetermined source coding and a predetermined channel coding for transmission of a wanted signal for cach transmission direction; and

means in the mobile station for measuring, at the time of a call between the mobile station and the network entity, transmission quality in a downlink direction from said network to the mobile station, for transmitting to said network entity information representing the measured transmission quality in said downlink direction, and in the network entity for measuring transmission quality in an uplink direction from the mobile station to said network entity,

wherein the network entity comprises mode control means (71) for selecting for each transmission direction, one of said coding modes, on the basis of information representing the respective measured transmission quality in the corresponding transmission direction, and

wherein said network entity, for selecting one of said coding modes for the uplink direction, comprises means for comparing the measured transmission quality in the up link direction with at least one predetermined threshold which is a predetermined value of a signal to interference ratio.

7. The mobile radio system claimed in claim 6, wherein said comparing means, when comparing the measured transmission quality in the uplink direction with at least one predetermined threshold, uses two sets of at least one threshold:

a first set if the measured transmission quality deteriorates, and the second set if the measured transmission quality improves.

8. The mobile radio system claimed in claim 6, wherein said means for measuring transmission quality in the downlink and uplink directions comprise means for determining at least one of the following:

the bit error rate of the received signal,

the power of the received signal,

the distance between the mobile station and the network entity,

an estimate of the impulse response of the transmission channel,

the time alignment,

the signal to noise ratio,

the signal to interference ratio, and

the traffic load.

9. The mobile radio system claimed in claim 6, wherein said mode control means allows for at least one of the following:

a required quality level for said call,

a required quality level for at least one transmission direction and for said call,

a type of service carried by said call, and

traffic load.

10. The mobile radio system claimed in claim 6, wherein a coding mode is selected in such a manner as to limit the quantity of resource allocated in each transmission direction and/or to optimize quality.

11. The system according to claim 6, wherein said mode control means also allows for at least one of the following:

a required quality level for said call,

a required quality level for at least one transmission direction and for said call,

a type of service carried by said call, and

traffic load.

12. The system according to claim 6, wherein said mode control means selects said one of said coding modes in such a manner as to limit the quantity of resource allocated in each transmission direction and/or to optimize quality.

19. The mobile radio system according to claim 6, wherein said mode control means selects a source coding and a channel coding.

22. The mobile radio system as claimed in claim 6, wherein said network entity is a base transceiver station.

13. A network entity for a mobile radio system including at least one mobile station and capable of bi-directionally exchanging digital signals between the network entity and the at least one mobile station, the system providing at least two coding modes, each mode corresponding to a predetermined source coding and a predetermined channel coding for transmission of a wanted signal for each transmission direction,

said network entity comprising a mode control means (71) for selecting, for each transmission direction, one of said coding modes, on the basis of information representing a respective measured transmission quality in the corresponding direction,

wherein the mode control means (71), for selecting one of said coding modes for an uplink direction from said mobile station to said network entity compares the measured transmission quality in the uplink direction with at least one predetermined threshold which is a predetermined value of a signal to interference ratio.

14. The network entity as claimed in claim 13, wherein the mode control means (71), when comparing the measured transmission quality in the uplink direction with at least one predetermined threshold, uses two sets of at least one threshold:

a first set if the transmission quality deteriorates, and the second set if the transmission quality improves.

15. The network entity claimed in claim 13, wherein said mode control means for selecting also allows for at least one of the following:

a required quality level for said call,

a required quality level for at least one transmission direction and for said call,

a type of service carried by said call, and

traffic load.

16. The network entity according to claim 13, wherein said mode control means also allows for at least one of the following:

a required quality level for said call,

a required quality level for at least one transmission direction and for said call,

a type of service carried try said call, and

traffic load.

17. The network entity according to claim 13, wherein said mode control means selects said one of said coding modes in such a manner as to limit the quantity of resource allocated in each transmission direction and/or to optimize quality.

20. The network equipment according to claim 13, wherein said mode control means selects a source coding and a channel coding.

23. The network entity as claimed in claim 13, wherein said network entity is a base transceiver station.

24. The network entity as claimed in claim 13, further comprising means for determining at least one of the following in the uplink direction:

the bit error rate of the received signal,

the power of the received signal,

the distance between the mobile station and the network entity,

an estimate of the impulse response of the transmission channel,

the time alignment,

the signal to noise ratio,

the signal to interference ratio, and

the traffic load.