Mobile communication system and transmission mode switching method used therefor as well as recording medium having program of the same method recorded therein

• US 20020119757A1
• Filed: 02/27/2002
• Published: 08/29/2002
• Est. Priority Date: 02/28/2001
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Hamabe, Kojiro
• Granted Patent: US 7,050,761 B2
• Time in Patent Office: Days
• US Class Current: 455/69
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04L 1/0034 where the transmitter decides based on inferences, e.g. use of implicit signalling
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

To provide a mobile communication system capable of easily performing selection of an optimal transmission mode. Upon receiving a receiving error notice from a mobile station, a transmission mode switching selecting portion of a base station forwards an instruction to switch a transmission mode to a mode slower than a current transmission mode to a modulation/coding portion. After receiving the receiving error notice, if the receiving error notice is not continuously received for a predetermined number of blocks Ns, the transmission mode switching selecting portion forwards an instruction to switch a transmission mode to a mode faster than the current transmission mode to the modulation/coding portion. The modulation/coding portion switches the modulation/coding code to any one of a QPSK modulation/coding circuit, a 16QAM modulation/coding circuit and a 64QAM modulation/coding circuit in response to the switching instruction and performs modulation/coding in the circuit switched to.

Claims

1. A mobile communication system capable of selecting any one of a plurality of transmission modes used for data transmission of a unit of block between a base station controlled by a base station control apparatus and a mobile station, comprising:

detecting means that is provided in said mobile station and detects occurrence of a receiving error of a unit of block in said data transmission; and

switching selecting means for switching said transmission modes based on the occurrence of said receiving error to be detected by said detecting means.

2. The mobile communication system according to claim 1,

wherein said switching selecting means is configured to switch said transmission mode to a mode slower than a current mode when detection of the occurrence of said receiving error by said detecting means reaches n times (n is an integer equal to or more than one).

3. The mobile communication system according to claim 1,

wherein said switching selecting means is configured to switch said transmission mode to a mode faster than a current mode when detection of successful receipt of said data transmission by said detecting means continues for m times (m is an integer larger than n).

4. The mobile communication system according to claim 1,

wherein said switching selecting means is configured to switch said transmission mode to a mode faster than a current mode when a receiving error rate within a predetermined time set in advance becomes a predetermined value or less.

5. The mobile communication system according to claim 3,

wherein said switching selecting means is configured to determine switching to said faster mode according to a target block error rate in said data transmission.

6. The mobile communication system according to claim 1,

wherein said switching selecting means is configured to switch said transmission mode to a mode slower than a current mode when a block error rate in a predetermined first number of blocks set in advance is larger than a first predetermined block error rate set in advance and switch said transmission mode to a mode faster than the current mode when a block error rate in a second predetermined number of blocks set in advance (second predetermined number of blocks>

first predetermined number of blocks) is smaller than a second predetermined block error rate set in advance and to a mode slower than the current mode when the block error rate in the second predetermined number of blocks is equal to or larger than a third predetermined block error rate set in advance.

7. The mobile communication system according to claim 6,

wherein said switching selecting means is configured to determine said first predetermined number of blocks, said second predetermined number of blocks, said first predetermined block error rate, said second predetermined block error rate and said third predetermined block error rate according to a target block error rate in said data transmission.

8. The mobile communication system according to claim 1,

wherein said switching selecting means is configured to switch said transmission mode to a mode slower than a current mode when a block error rate in predetermined first time set in advance is larger than a first predetermined block error rate set in advance and switch said transmission mode to a mode faster than the current mode when a block error rate in second predetermined time set in advance (second predetermined time >

first predetermined time) is smaller than a second predetermined block error rate set in advance and to a mode slower than the current mode when the block error rate in the second predetermined time is equal to or larger than a third predetermined block error rate set in advance.

9. The mobile communication system according to claim 8,

wherein said switching selecting means is configured to make the predetermined time for the condition for switching said transmission mode to said faster mode shorter than the predetermined time for the condition for switching said transmission mode to said slower mode.

10. The mobile communication system according to claim 9,

wherein said switching selecting means is configured to make a rate of the predetermined time for switching said transmission mode to said faster mode and the predetermined time for switching said transmission mode to said slower mode equal to a ratio of data transmission speeds.

11. The mobile communication system according to claim 8,

wherein said switching selecting means is configured to determine said first predetermined time, said second predetermined time, said first predetermined block error rate, said second predetermined block error rate and said third predetermined block error rate according to a target block error rate in said data transmission.

12. The mobile communication system according to claim 1,

wherein said switching selecting means is disposed any one of said base station control apparatus, said base station and said mobile station.

14. The transmission mode switching method according to claim 13,

wherein said second step is arranged to switch said transmission mode to a mode slower than a current mode when detection of the occurrence of said receiving error in said first step reaches n times (n is an integer equal to or more than one).

15. The transmission mode switching method according to claim 13,

wherein said second step is arranged to switch said transmission mode to a mode faster than a current mode when detection of successful receipt of said data transmission in said first step continues for m times (m is an integer larger than n).

16. The transmission mode switching method according to claim 13,

wherein said second step is arranged to switch said transmission mode to a mode faster than a current mode when a receiving error rate within a predetermined time set in advance becomes a predetermined value or less.

17. The transmission mode switching method according to claim 15,

wherein said second step is arranged to determine switching to said faster mode according to a target block error rate in said data transmission.

18. The transmission mode switching method according to claim 13,

wherein said second step is arranged to switch said transmission mode to a mode slower than a current mode when a block error rate in a predetermined first number of blocks set in advance is larger than a first predetermined block error rate set in advance and switch said transmission mode to a mode faster than the current mode when a block error rate in a second predetermined number of blocks set in advance (second predetermined number of blocks>

first predetermined number of blocks) is smaller than a second predetermined block error rate set in advance and to a mode slower than the current mode when the block error rate in the second predetermined number of blocks is equal to or larger than a third predetermined block error rate set in advance.

19. The transmission mode switching method according to claim 18,

wherein said second step is arranged to determine said first predetermined number of blocks, said second predetermined number of blocks, said first predetermined block error rate, said second predetermined block error rate and said third predetermined block error rate according to a target block error rate in said data transmission.

20. The transmission mode switching method according to claim 13,

wherein said second step is arranged to switch said transmission mode to a mode slower than a current mode when a block error rate in predetermined first time set in advance is larger than a first predetermined block error rate set in advance and switch said transmission mode to a mode faster than the current mode when a block error rate in second predetermined time set in advance (second predetermined time>

first predetermined time) is smaller than a second predetermined block error rate set in advance and to a mode slower than the current mode when the block error rate in the second predetermined time is equal to or larger than a third predetermined block error rate set in advance.

21. The transmission mode switching method according to claim 20,

wherein said second step is arranged to make the predetermined time for the condition for switching said transmission mode to said faster mode shorter than the predetermined time for the condition for switching said transmission mode to said slower mode.

22. The transmission mode switching method according to claim 21,

wherein said second step is arranged to make a rate of the predetermined time for switching said transmission mode to said faster mode and the predetermined time for switching said transmission mode to said slower mode equal to a ratio of data transmission speeds.

23. The transmission mode switching method according to claim 20,

wherein said second step is arranged to determine said first predetermined time, said second predetermined time, said first predetermined block error rate, said second predetermined block error rate and said third predetermined block error rate according to a target block error rate in said data transmission.

24. The transmission mode switching method according to claim 13,

wherein said second step is disposed any one of said base station control apparatus, said base station and said mobile station.

13. A transmission mode switching method capable of selecting any one of a plurality of transmission modes used for data transmission of a unit of block between a base station controlled by a base station control apparatus and a mobile station, comprising:

a first step of detecting occurrence of a receiving error of a unit of block in said data transmission in said mobile station; and

a second step of performing switching of said transmission modes based on the occurrence of said receiving error to be detected in said first step.

25. A recording medium having recorded therein a program of a transmission mode switching method of a mobile communication system capable of selecting any one of a plurality of transmission mode used for data transmission of a unit of block between a base station controlled by a base station control apparatus and a mobile station,

wherein the program causes a computer to execute processing for detecting occurrence of a receiving error of a unit of block in said data transmission in said mobile station and processing for performing switching of said transmission mode based on the occurrence of said receiving error to be detected.