Mobile communication system, base station, and communication control method

• US 20040077357A1
• Filed: 12/04/2003
• Published: 04/22/2004
• Est. Priority Date: 02/14/2001
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Nakada, Suguru
• Granted Patent: US 7,738,889 B2
• Time in Patent Office: Days
• US Class Current: 455/452.1
• CPC Class Codes: H04B 1/70755 Setting of lock conditions, e.g. threshold
• CPC Class Codes: H04B 1/7113 Determination of path profile
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception

Abstract

A wireless communication system comprising a transmitting station and a receiving station, and a control method therefore. A mobile station (101) as the transmitting station has a facility for transmitting a preamble signal to a base station (102) as the receiving station before transmission of information data from the mobile station (101) to the base station (102). On the other hand, the base station (102) has a facility for performing path detection by using a signal threshold for the preamble signal received from the mobile station (101), a facility for performing further path detection by using another threshold for the received preamble signal if paths are detected in the path detection, and a facility for setting path information of the paths detected by using the plurality of thresholds for a receiver (206) installed in the base station (102) so as to perform a path diversity reception. In the wireless communication system and the control method therefore, the receiver (206) of the base station (102) receives information data transmitted from the mobile station (101).

Claims

1. In a receiving station for receiving a preamble signal transmitted from a transmitting station before transmission of information data from said transmitting station to said receiving station, a communication control method comprising the steps of:

performing path detection by using a single threshold for the preamble signal from said transmitting station;

performing further path detection by using another threshold for said received preamble signal if paths are detected in said path detection;

setting information of the paths detected by using said plurality of thresholds for a receiver installed in said receiving station so as to perform a path diversity reception; and

receiving information data transmitted from said transmitting station by means of said receiver.

5. The communication control method according to one of claims 1 to 4, wherein said transmitting station and said receiving station are a mobile station and a wireless base station forming a land mobile communication system, respectively.

6. The communication control method according to one of claims 1 to 4, wherein said transmitting station and said receiving station are wireless terminals forming a wireless LAN (local area network) system, respectively.

7. The communication control method according to one of claims 1 to 4, wherein said receiver performs maximum ratio combining of diversity branches on the basis of said set path information.

8. The communication control method according to one of claims 1 to 4, wherein said preamble signal is a signal for acquiring authorization of transmitting said information data from said transmitting station to said receiving station in a random access communication and wherein said transmitting station transmits said information data when receiving the authorization of the transmission from said receiving station in response to said preamble signal.

2. In a receiving station for receiving a preamble signal transmitted from a transmitting station before transmission of information data from said transmitting station to said receiving station, a communication control method comprising the steps of:

performing path detection by using a single threshold for the preamble signal from said transmitting station;

setting up one or more append paths before and/or after (on a time basis) at least one path among detected paths if the paths are detected in said path detection;

setting information of said detected paths and said append paths for a receiver installed in said receiving station so as to perform a path diversity reception; and

receiving information data transmitted from said transmitting station by means of said receiver.

3. In a receiving station for receiving a preamble signal transmitted from a transmitting station before transmission of information data from said transmitting station to said receiving station, a communication control method comprising the steps of:

performing path detection by using a single threshold for the preamble signal from said transmitting station;

performing further path detection by using another threshold for said received preamble signal if paths are detected in said path detection;

setting up one or more append paths before and/or after (on a time basis) at least one path among detected paths;

setting information of the paths detected by using said plurality of thresholds and said append paths for a receiver installed in said receiving station so as to perform a path diversity reception; and

receiving information data transmitted from said transmitting station by means of said receiver.

4. In a receiving station for receiving a preamble signal transmitted from a transmitting station before transmission of information data from said transmitting station to said receiving station, a communication control method comprising the steps of:

performing path detection by using a single threshold for the preamble signal from said transmitting station;

setting up one or more append paths before and/or after (on a time basis) at least one path among detected paths if the paths are detected in said path detection;

performing further path detection by using another threshold for said preamble signal;

setting information of said append paths and the paths detected by using said plurality of thresholds for a receiver installed in said receiving station so as to perform a path diversity reception; and

receiving information data transmitted from said transmitting station by means of said receiver.

9. A wireless communication system having a transmitting station and a receiving station,

wherein said transmitting station comprising:

means for transmitting a preamble signal to said receiving station before transmission of information data from said transmitting station to said receiving station,

wherein said receiving station comprising;

means for performing path detection by using a single threshold for said preamble signal received from said transmitting station;

means for performing further path detection by using another threshold for said received preamble signal if paths are detected in said path detection; and

means for setting information of the paths detected by using said plurality of thresholds for a receiver installed in said receiving station so as to perform a path diversity reception, and

wherein said receiver then receives said information data transmitted from said transmitting station.

10. A wireless communication system having a transmitting station and a receiving station,

wherein said transmitting station comprising:

means for transmitting a preamble signal to said receiving station before transmission of information data from said transmitting station to said receiving station,

wherein said receiving station comprising;

means for performing path detection by using a single threshold for said preamble signal received from said transmitting station;

means for setting up one or more append paths before and/or after (on a time basis) at least one path among detected paths if the paths are detected in said path detection; and

means for setting information of said detected paths and the append paths for a receiver installed in said receiving station so as to perform a path diversity reception, and

wherein said receiver then receives said information data transmitted from said transmitting station.

13. The wireless communication system according to one of claims 9 to 12, wherein said transmitting station and said receiving station are a mobile station and a wireless base station forming a land mobile communication system, respectively.

14. The wireless communication system according to one-of claims 9 to 12, wherein said transmitting station and said receiving station are wireless terminals forming a wireless LAN system, respectively.

15. The wireless communication system according to one of claims 9 to 12, wherein said receiver performs maximum ratio combining of diversity branches on the basis of said set path information.

16. The wireless communication system according to one of claims 9 to 12, wherein said preamble signal is a signal for acquiring authorization of transmitting said information data from said transmitting station to said receiving station in a random access communication and wherein said transmitting station transmits said information data when receiving the authorization of the transmission from said receiving station in response to said preamble signal.

11. A wireless communication system having a transmitting station and a receiving station,

wherein said transmitting station comprising:

means for transmitting a preamble signal to said receiving station before transmission of information data from said transmitting station to said receiving station,

wherein said receiving station comprising;

means for performing path detection by using a single threshold for said preamble signal received from said transmitting station;

means for performing further path detection by using another threshold for said received preamble signal if paths are detected in said path detection;

means for setting up one or more append paths before and/or after (on a time basis) at leas one path among paths detected by using said plurality of thresholds; and

means for setting information of the paths detected by using said plurality of thresholds and said append paths for a receiver installed in said receiving station so as to perform a path diversity reception, and

wherein said receiver then receives said information data transmitted from said transmitting station.

12. A wireless communication system having a transmitting station and a receiving station,

wherein said transmitting station comprising:

means for transmitting a preamble signal to said receiving station before transmission of information data from said transmitting station to said receiving station,

wherein said receiving station comprising;

means for performing path detection by using a single threshold for said preamble signal received from said transmitting station;

means for setting up one or more append paths before and/or after (on a time basis) at least one path among detected paths if the paths are detected in said path detection;

means for performing further path detection by using another threshold for said received preamble signal; and

means for setting information of said append paths and said paths detected by using said plurality of thresholds for a receiver installed in said receiving station so as to perform a path diversity reception, and

wherein said receiver then receives said information data transmitted from said transmitting station.

17. A communication control method for a mobile communication system using a random access for one of uplink channels from a mobile station to a base station, comprising the steps of:

in said mobile station,

transmitting a preamble signal for acquiring authorization of message signal transmission;

in said base station,

performing path detection by using a single preamble threshold for a path of said preamble signal from said mobile station, and, if a path exceeding said single preamble threshold is detected and the message signal can be received, transmitting a signal indicating the authorization of message signal transmission to said mobile station;

subsequently to the transmission of said signal indicating the authorization of message signal transmission, performing path detection by using another preamble threshold for the paths of said previously received preamble signal;

setting information of the paths detected by using said preamble thresholds for a receiver installed in said receiving station so as to perform a path diversity reception; and

receiving the message signal transmitted from said mobile station by means of said receiver.

18. The communication control method according to claim 17, wherein said single preamble threshold is higher than or equal to said another preamble threshold.

20. The communication control method according to claim 17, further comprising steps of providing append paths before and/or after (on a time basis) at least one path among said detected paths in said base station and setting path information of said detected paths and said append paths to said path diversity receiver.

19. A communication control method for a mobile communication system using a random access for one of uplink channels from a mobile station to a base station, comprising the steps of:

in said mobile station,

transmitting a preamble signal for acquiring authorization of message signal transmission;

in said base station,

performing path detection by using a single preamble threshold for a path of said preamble signal from said mobile station, and, if a path exceeding said single preamble threshold is detected and the message signal can be received, transmitting a signal indicating the authorization of message signal transmission to said mobile station;

setting up one or more append paths before and/or after (on a time basis) at least one path among said detected paths;

setting information of said detected paths and said append paths for a receiver installed in said receiving station so as to perform a path diversity reception; and

receiving the message signal from said mobile station by means of said receiver.

21. A mobile communication system using a random access for one of uplink channels from a mobile station to a base station,

wherein said mobile station comprises:

means for transmitting a preamble signal for acquiring authorization of message signal transmission; and

means for transmitting a message signal to said base station when receiving a signal indicating the authorization of message signal transmission from said base station,

wherein said base station having a plurality of preamble thresholds comprises;

means for performing path detection by using a single preamble threshold for a path of said preamble signal from said mobile station, and, if a path exceeding said single preamble threshold is detected and the message signal can be received, transmitting a signal indicating the authorization of message signal transmission to said mobile station;

subsequently to the transmission of said signal indicating the authorization of message signal transmission, performing path detection by using another preamble threshold for the paths of said previously received preamble signal; and

setting information of the paths detected by using said plurality of preamble thresholds for a receiver installed in said receiving station so as to perform a path diversity reception; and

wherein said receiver receives the message signal from said mobile station.

22. The mobile communication system according to claim 21, wherein said single preamble threshold is higher than or equal to said another preamble threshold.

24. The mobile communication system according to claim 21 or 22, wherein said base station has means for setting path information with at least one path among said detected paths provided with the append paths before and/or after on a time basis to said path diversity receiver.

25. The mobile communication system according to claim 21,

wherein a baseband signal processing unit of said base station comprises:

a path detector receiving an input of a received baseband signal demodulated by a demodulator;

a rake receiver receiving an input of said received baseband signal;

a control unit for exchanging control information and send/receive data with a host device; and

a code generator receiving an input of code generation information from said control unit and outputting a transmitted baseband signal to a modulator,

wherein said path detector measures a cross correlation between the input received baseband signal and code sequences forming said preamble signal previously determined to be used with the mobile station and detects as a path a portion where a correlation value or a power level is the maximum, the path detector comprising means for performing threshold processing by using a first preamble threshold for the detected path and notifying said control unit of a result of the threshold processing as preamble signal detection information,

wherein said control unit comprises means for receiving said preamble signal detection information and supplying code generation information to said code generator,

wherein said code generator comprises means for generating code sequences forming an acknowledgement signal indicating authorization of a message transmission or a negative acknowledgement signal indicating an impossible message transmission on the basis of said code generation information from said control unit and transmitting it as a transmitted baseband signal to said modulator,

wherein, subsequently to the transmission of said acknowledgement signal, said path detector performs path detection again by using a second preamble threshold lower than or equal to said first preamble threshold and notifies said rake receiver of the path information of paths clearing said second preamble threshold, and

wherein said rake receiver sets delays of the path information from said path detector to correlators forming rake fingers of said rake receiver, demodulates the message signal from said received baseband signal, and transmits the demodulated message signal as message data to said control unit.

27. The mobile communication system according to claim 21, wherein said path detector adds one or more append paths before and/or after at least one path among the paths clearing said preamble thresholds and notifies said rake receiver of their path information.

23. A mobile communication system using a random access for one of uplink channels from a mobile station to a base station,

wherein said mobile station comprises:

means for transmitting a preamble signal indicating a request for authorization of message signal transmission; and

means for transmitting the message signal to said base station when receiving a signal indicating authorization of message signal transmission from said base station,

wherein said base station comprises;

means for performing path detection by using a single preamble threshold for a path of said preamble signal from said mobile station, and, if a path exceeding said single preamble threshold is detected and the message signal can be received, transmitting a signal indicating the authorization of message signal transmission to said mobile station;

means for providing append paths before and/or after (on a time basis) at least one path among said detected paths; and

means for setting path information of said detected paths and said append paths for a receiver installed in said receiving station so as to perform a path diversity reception; and

wherein said receiver receives the message signal from said mobile station.

26. The mobile communication system according to claim 23,

wherein a baseband signal processing unit of said base station comprises:

a path detector receiving an input of a received baseband signal demodulated by a demodulator;

a rake receiver receiving an input of said received baseband signal;

a control unit for exchanging control information and send/receive data with a host device; and

a code generator receiving an input of code generation information from said control unit and outputting a transmitted baseband signal to a modulator,

wherein said path detector measures a cross correlation between the input received baseband signal and code sequences forming said preamble signal previously determined to be used with the mobile station and detects as a path a portion where a correlation value or a power level is the maximum, the path detector comprising means for performing threshold processing by using a preamble threshold for the detected path and notifying said control unit of a result of the threshold processing as preamble signal detection information,

wherein said control unit comprises means for receiving said preamble signal detection information and supplying code generation information to said code generator,

wherein said code generator comprises means for generating code sequences forming an acknowledgement signal indicating authorization of a message transmission or a negative acknowledgement signal indicating an impossible message transmission on the basis of said code generation information from said control unit and transmitting it as a transmitted baseband signal to said modulator,

wherein, said path detector comprises means for adding one or more append paths before and/or after (on a time basis) at least one path among paths clearing said preamble threshold determination and notifying said rake receiver of the path information of said paths clearing said preamble threshold determination and said append paths to said rake receiver, subsequently to the transmission of said acknowledgement signal, and

wherein said rake receiver sets delays of said path information from said path detector to correlators forming rake fingers of said rake receiver, demodulates the message signal from said received baseband signal, and transmits the demodulated message signal as message data to said control unit.

28. A receiving station for performing a wireless communication with a transmitting station, comprising:

means for receiving a preamble signal transmitted from said transmitting station before transmission of information data from said transmitting station to said receiving station and performing path detection by using a single threshold for said preamble signal;

means for performing further path detection by using another threshold for said received preamble signal if a path is detected; and

means for setting path information of the path detected by using said another threshold for a receiver installed in said receiving station so as to perform a path diversity reception,

wherein said receiver then receives the information data transmitted from said transmitting station.

30. The receiving station according to claim 28, further comprising means for setting up one or more append paths before and/or after (on a time basis) at least one path among the detected paths and means for setting path information of the paths and said append paths to said receiver for performing the path diversity reception.

29. A receiving station for performing a wireless communication with a transmitting station, comprising:

means for receiving a preamble signal transmitted from said transmitting station before transmission of information data from said transmitting station to said receiving station and performing path detection by using a single threshold for said preamble signal;

means for setting up one or more append paths before and/or after (on a time basis) at least one path among detected paths if the paths are detected in said path detection; and

means for setting path information of said detected paths and said append paths for a receiver installed in said receiving station so as to perform a path diversity reception,

wherein said receiver then receives the information data transmitted from said transmitting station.

31. A base station for a mobile communication system using a random access for one of uplink channels from a mobile station to the base station, having a plurality of preamble thresholds, comprising:

means for performing path detection by using a single preamble threshold for a path of a preamble signal for conveying a request for a message signal transmission from said mobile station to said base station and, if a path exceeding said single preamble threshold is detected and a message signal can be received, transmitting a signal indicating authorization of message signal transmission to said mobile station;

means for performing path detection by using another preamble threshold for the paths of the previously received preamble signal subsequently to said transmission of the signal indicating the authorization of the message signal transmission; and

means for setting information of the paths detected by using said preamble thresholds for a receiver installed in said base station so as to perform a path diversity reception, and

wherein said receiver receives the message signal from said mobile station.

32. A base station for a mobile communication system using a random access for one of uplink channels from a mobile station to the base station, comprising:

means for performing path detection by using a single preamble threshold for a path of a preamble signal for conveying a request for a message signal transmission from said mobile station to said base station and, if a path exceeding said single preamble threshold is detected and a message signal can be received, transmitting a signal indicating authorization of message signal transmission to said mobile station;

means for providing append paths before and/or after (on a time basis) at least one path among the detected paths; and

means for setting path information of said detected paths and said append paths for a receiver installed in said base station so as to perform a path diversity reception, and

wherein said receiver receives the message signal from said mobile station.

33. A base station, comprising:

a path detector receiving an input of a received baseband signal demodulated by a demodulator;

a rake receiver receiving an input of said received baseband signal;

a control unit for exchanging control information and send/receive data with a host device; and

a code generator receiving an input of code generation information from said control unit and outputting a transmitted baseband signal to a modulator,

wherein said path detector measures a cross correlation between the input received baseband signal and code sequences forming a preamble signal previously determined to be used with the mobile station and detects as a path a portion where a correlation value or a power level is the maximum, the path detector comprising means for performing threshold processing by using a first preamble threshold for the detected path and notifying said control unit of a result of the threshold processing as preamble signal detection information,

wherein said control unit comprises means for receiving said preamble signal detection information and transmitting code generation information to said code generator,

wherein said code generator comprises means for generating code sequences forming an acknowledgement signal indicating authorization of a message transmission or a negative acknowledgement signal indicating an impossible message transmission on the basis of said code generation information from said control unit and transmitting it as a transmitted baseband signal to said modulator,

wherein, subsequently to the transmission of said acknowledgement signal, said path detector performs threshold processing again for the detected path by using a second preamble threshold lower than or equal to said first preamble threshold and notifies said rake receiver of the path information of paths clearing said second preamble threshold, and

wherein said rake receiver sets delays of the path information to correlators forming said rake receiver, demodulates the message signal from said received baseband signal, and transmits the demodulated message signal as message data to said control unit.

35. The base station according to claim 33 or 34, wherein said path detector adds a plurality of append paths spaced at given intervals before and after the path clearing said preamble threshold determination and notifies said rake receiver of their path information.

34. A base station, comprising:

a path detector receiving an input of a received baseband signal demodulated by a demodulator;

a rake receiver receiving an input of said received baseband signal;

a control unit for exchanging control information and send/receive data with a host device; and

a code generator receiving an input of code generation information from said control unit and outputting a transmitted baseband signal to a modulator,

wherein said path detector measures a cross correlation between the input received baseband signal and code sequences forming a preamble signal previously determined to be used with the mobile station and detects as a path a portion where a correlation value or a power level is the maximum, the path detector comprising means for performing threshold processing by using a preamble threshold for the detected path and notifying said control unit of a result of the threshold processing as preamble signal detection information,

wherein said control unit comprises means for receiving said preamble signal detection information and transmitting code generation information to said code generator,

wherein said code generator comprises means for generating code sequences forming an acknowledgement signal indicating authorization of a message transmission or a negative acknowledgement signal indicating an impossible message transmission on the basis of said code generation information from said control unit and transmitting it as a transmitted baseband signal to said modulator,

wherein said path detector comprises means for adding append paths to paths clearing the preamble threshold determination and notifying said rake receiver of their path information, subsequently to the transmission of said acknowledgement signal, and

wherein said rake receiver sets delays of said path information to correlators forming said rake receiver, demodulates the message signal from said received baseband signal, and transmits the demodulated message signal as message data to said control unit.