Mobile communication system, transmission mode switching method, and recording medium having transmission mode switching method recorded thereon

• US 7,050,761 B2
• Filed: 02/27/2002
• Issued: 05/23/2006
• Est. Priority Date: 02/28/2001
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Hamabe, Kojiro
• Primary Examiner(s): Chin, Vivian
• Assistant Examiner(s): TRAN, TUAN A
• Application Number:
  US10/083,477
• Publication Number:
  US 20020119757A1
• Time in Patent Office: 1,546 Days
• Field of Search: 455/67.11, 455/13, 455/67.16, 455/550.1, 455/68, 455/552.1, 455/69, 4552261- 2, 455/415, 455/419, 370235-236, 370331-333, 370/242, 370/245, 370/437, 370/465, 714708-709, 714759-760, 375220-222, 37524026- 27
• 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 for transmitting data, in a unit of a block of data, in any one of a plurality of transmission modes, said system comprising:

a base station;

a base station control apparatus for controlling said base station;

a mobile station comprising a detecting unit for detecting a receiving error in a unit of a block of data during the data transmission;

switching selecting means for switching the transmission mode, based on the detection of the receiving error,

wherein said switching selecting means is configured to switch the transmission mode to a first slow mode, which is slower than a current mode, when the block error rate in a first predetermined number of blocks is larger than a first predetermined block error rate, to switch the transmission mode to a fast mode, which is faster than the current mode, when the block error rate in a second predetermined number of blocks is smaller than a second predetermined block error rate, and to switch the transmission mode to a second slow 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, where the second predetermined number of blocks is greater than the first predetermined number of blocks.

2. The mobile communication system according to claim 1,

wherein said switching selecting means configured to switch said transmission mode to the fast mode when successful receipt of the data transmission by said detecting means has been detected m times, (where m is an integer larger than) 2.

3. The mobile communication system according to claim 2,

wherein said switching selecting means is configured to switch to the fast mode based on a target block error rate in the data transmission.

4. The mobile communication system according to claim 1,

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

5. The mobile communication system according to claim 1,

wherein said switching selecting means is disposed in said base station.

6. The mobile communication system according to claim 1,

wherein said switching selecting means is disposed in said base station control apparatus.

7. The mobile communication system according to claim 1,

wherein said switching selecting means is disposed in said mobile station.

8. The mobile communication system according to claim 1, wherein the first slow mode and the second slow mode are the same.

9. A mobile communication system for transmitting data, in a unit of a block of data, in any one of a plurality of transmission modes, said system comprising:

a base station;

a base station control apparatus for controlling said base station;

a mobile station comprising a detecting unit for detecting a receiving error in a unit of a block of data during the data transmission;

switching selecting means for switching the transmission mode, based on the detection of the receiving error,

wherein said switching selecting means configured to switch the transmission mode to a first slow mode, which is slower than a current mode, when the block error rate during a first predetermined time period is larger than a first predetermined block error rate, to switch the transmission mode to a fast mode, which is faster than the current mode, when the block error rate during a second predetermined time period is smaller than a second predetermined block error rate, and to switch the transmission mode to a second slow mode, which is slower than the current mode, when the block error rate in the second predetermined time period is equal to or larger than a third predetermined block error rate, where the second predetermined time period is greater than the first predetermined time period.

10. The mobile communication system according to claim 9,

wherein the second predetermined time period is shorter than the third predetermined time period.

11. The mobile communication system according to claim 10,

wherein the second predetermined time period and the third predetermined time period are based on a ratio of data transmission speeds in the fast mode and the second slow mode.

12. The mobile communication system according to claims 9,

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

13. The mobile communication system according to claim 9, wherein the first slow mode and the second slow mode are the same.

14. The mobile communication system according to claim 9,

wherein said switching selecting means is disposed in said base station.

15. The mobile communication system according to claim 9,

wherein said switching selecting means is disposed in said base station control apparatus.

16. The mobile communication system according to claim 9,

wherein said switching selecting means is disposed in said mobile station.

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

detecting a receiving error in a unit of a block of data during the data transmission to said mobile station; and

on detection of the receiving error, switching the transmission mode to a first slow mode, which is slower than a current mode, when the block error rate in a first predetermined number of blocks is larger than a first predetermined block error rate, switching the transmission mode to a fast mode, which is faster than the current mode, when the block error rate in a second predetermined number of blocks is smaller than a second predetermined block error rate, and switching the transmission mode to a second slow 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, where the second predetermined number of blocks is greater than the first predetermined number of blocks.

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

wherein transmission mode is switched to the fast mode when successful receipt of the data transmission has been detected m times, where (m is an integer larger than) 2.

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

wherein switching to the fast mode is based on a target block error rate in the data transmission.

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

wherein the first predetermined number of blocks, the second predetermined number of blocks, the first predetermined block error rate, the second predetermined block error rate, and the third predetermined block error rate are based on a target block error rate in the data transmission.

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

detecting a receiving error in a unit of a block of data during the data transmission to said mobile station; and

on detection of the receiving error, switching the transmission mode to a first slow mode, slower than a current mode, when the block error rate in a first predetermined time period is larger than a first predetermined block error rate, switching the transmission mode to a fast mode, faster than the current mode, when the block error rate in a second predetermined time period is smaller than a second predetermined block error rate, and switching the transmission mode to a second slow mode, slower than the current mode, when the block error rate in the second predetermined time period is equal to or larger than a third predetermined block error rate, where the second predetermined time period is greater than the first predetermined time period.

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

wherein the predetermined time period for switching the transmission mode to the fast mode is shorter than the predetermined time period for switching the transmission mode to the second slow mode.

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

wherein the predetermined time period for switching the transmission mode to the fast mode and the predetermined time period for switching the transmission mode to the second slow mode are based on a ratio of data transmission speeds.

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

the first predetermined time period, the second predetermined time period, the first predetermined block error rate, the second predetermined block error rate, and the third predetermined block error rate are based on a target block error rate in the data transmission.

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 modes used for data transmission of a unit of a block of data between a base station controlled by a base station control apparatus and a mobile station, wherein the program causes a computer to:

detect a receiving error of a unit of a block of data in the data transmission to said mobile station, and on detection of the receiving error, switch the transmission mode to a first slow mode, which is slower than a current mode, when the block error rate in a first predetermined number of blocks is larger than a first predetermined block error rate, switch the transmission mode to a fast made, which is faster than the current mode, when the block error rate in a second predetermined number of blocks is smaller than a second predetermined block error rate, and switch the transmission mode to a second slow 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, where the second predetermined number of blocks is greater than the first predetermined number of blocks.

26. 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 modes used for data transmission of a unit of a block of data between a base station controlled by a base station control apparatus and a mobile station, wherein the program causes a computer to:

detect a receiving error of a unit of a block of data in the data transmission to said mobile station, and on detection of the receiving error, switch the transmission mode to a first slow mode, slower than a current mode, when the block error rate in a first predetermined time period is larger than a first predetermined block error rate, switch the transmission mode to a fast mode, faster than the current mode, when the block error rate in a second predetermined time period is smaller than a second predetermined block error rate, and switch the transmission mode to a second slow mode, slower than the current mode, when the block error rate in the second predetermined time period is equal to or larger than a third predetermined block error rate, where the second predetermined time period is greater than the first predetermined time period.