TDMA radio communication system, and a base station and subscriber stations for radio communication

• US 6,930,993 B1
• Filed: 09/30/1998
• Issued: 08/16/2005
• Est. Priority Date: 09/30/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ito, Shuji, Hamada, Tomokazu, Kawabata, Takashi, Moritani, Youichi
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): HOANG, THAI D
• Application Number:
  US09/529,440
• Time in Patent Office: 2,512 Days
• Field of Search: 370328-330, 370/336, 370/337, 370/347, 455500-501, 455/506, 455/63.1, 455/67.13, 455/114.2, 4552261-2263
• US Class Current: 370/347
• CPC Class Codes: H04W 16/04 Traffic adaptive resource partitioning
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning

Abstract

In a TDMA communication system in which a base station communicates with a plurality of subscriber stations, communication time slots used in a wireless communication are allocated/arranged while avoiding an occurrence of interference.

In the case that interference (51) occurs in a communication time slot (411) of a line (71) through which the communication is made from a subscriber station (21) to a base station (1), interference information is registered into an interference time slot database (101) of the base station (1). When the communication time slots are reallocated and rearranged, a TDMA control unit of the base station (1) executes the communication time slot reallocation/rearrangement by referring to information registered in the interference time slot database (101), so that the occurrence of interference is avoided.

Claims

1. A base station apparatus for communicating with a plurality of subscriber stations on a TDMA wireless communication manner, comprising:

an interference time slot database for registering/storing thereinto a communication time slot in which interference happens to occur; and

a TDMA control unit for executing reallocation/rearrangement of time slots communicating with the respective subscriber stations in response to a change in a traffic based upon the interference time slot information of the interference time slot database;

wherein when interference is detected in a time slot received from a subscriber station, interference time slot information about said time slot in which interference is detected is registered into said interference time slot database;

the time slot reallocation/rearrangement are carried out based upon registered information of said interference time slot database such that said time slot in which interference is detected is reassigned to one or more time slots where no interference has been detected; and

also time slot reallocation/rearrangement information is transmitted to the respective subscriber stations, and

wherein time slot allocations/arrangements of all respective ones of said plurality of subscriber stations are changed once each super frame of a TDMA frame transmission structure, and wherein said base station transmits to the respective subscriber stations subsequent time slot reallocation/rearrangement information containing new time slot arrangements, over a plurality of frames within a super frame period.

2. A base station apparatus for communicating with a plurality of subscriber stations on a TDMA wireless communication manner, comprising:

an interference time slot database for registering/storing thereinto a communication time slot in which interference happens to occur; and

a TDMA control unit for executing reallocation/rearrangement of time slots communicating with the respective subscriber stations in response to a change in a traffic based upon the interference time slot information of the interference time slot database;

wherein when interference is detected in a time slot received from a subscriber station, interference time slot information about said time slot in which interference is detected is registered into said interference time slot database;

the time slot reallocation/rearrangement are carried out based upon registered information of said interference time slot database such that said time slot in which interference is detected is reassigned to one or more time slots where no interference has been detected; and

also time slot reallocation/rearrangement information is transmitted to the respective subscriber stations, and

wherein a service area of said base station is subdivided into a plurality of sectors, and wherein said TDMA control unit executes time slot reallocation/rearrangement first to subscriber stations in sectors where no interference has occurred, and then to subscriber stations in sectors where interference has occurred.

3. A TDMA wireless communication system in which a base station wireless-communicates with a plurality of subscriber stations by an up-stream line TDMA system and a down-stream line TDM system;

wherein the base station comprises;

an interference time slot database for registering/storing thereinto a communication time slot in which interference happens to occur; and

a TDMA control unit for executing reallocation/rearrangement of time slots communicating with the respective subscriber stations in response to a change in a traffic based upon the interference time slot information of the interference time slot database, and also transmits up-stream TDMA time slot reallocation/rearrangement information to the respective subscriber stations every predetermined frame in a down-stream TDM line;

wherein each of said subscriber stations monitors as to whether or not there is the up-stream TDMA time slot reallocation/rearrangement information addressed to the own subscriber station, which is transmitted from said base station every predetermined frame, and when said up-stream TDMA time slot reallocation/rearrangement information cannot be received, said subscriber station judges an occurrence of interference and transmits said occurrence of interference to the base station, and

wherein the base station which has received the occurrence of interference registers the interference occurrence information into said interference time slot database, and transmits time slot reallocation/rearrangement information to the respective subscriber stations based on the registered information saved in the interference time slot database.

4. A base station apparatus for communicating with a plurality of subscriber stations in a TDMA wireless communication manner, comprising:

an interference time slot database for registering/storing thereinto a communication time slot in which interference happens to occur; and

a TDMA control unit for executing reallocation/rearrangement of time slots communicating with the respective subscriber stations in response to a change in a traffic based upon the interference time slot information of the interference time slot database,

wherein when interference is detected in a time slot received from a subscriber station, said interference time slot information is registered into said interference time slot database;

the time slot reallocation/rearrangement are carried out based upon registered information of said interference time slot database; and

also time slot reallocation/rearrangement information is transmitted to the respective subscriber stations, and

wherein on the other hand, in the case that said interference time slot is received for a predetermined time period and the interference disappears, the interference time slot information registered into said interference time slot database is deleted therefrom.

5. The base station apparatus as claimed in claim 4, wherein said base station apparatus comprises an interference erroneous detection database, and registers said interference time slot information which has been deleted from said interference time slot database into said interference erroneous detection database.

6. The base station apparatus as claimed in claim 5, wherein when the same interference time slot information whose total number is larger than, or equal to a preselected number is registered into the interference erroneous detection database within a predetermined time period, said base station apparatus transmits an abnormal state to a central station for managing the base station.

7. The base station apparatus as claimed in claim 5, wherein when the same interference time slot information whose total number is larger than, or equal to a preselected number is registered into the interference erroneous detection database within a predetermined time period, said base station apparatus increases an interference judging threshold value used to detect an occurrence of interference.

8. A TDMA wireless communication system in which a base station communicates with a plurality of subscriber stations in a wireless manner,

wherein the base station comprises:

an interference time slot database for registering/storing thereinto a communication time slot in which interference happens to occur; and

a TDMA control unit for executing reallocation/rearrangement of time slots communicating with the respective subscriber stations in response to a change in a traffic based upon the interference time slot information of the interference time slot database,

wherein when interference is detected in a time slot received from the base station, said subscriber station transmits interference time slot information to said base station,

wherein the base station which has received the interference time slot information registers said interference time slot information into said interference time slot database, performs the time slot reallocation/rearrangement based upon registered information of said interference time slot database, transmits time slot reallocation/rearrangement information to the respective subscriber stations, and on the other hand, transmits an instruction signal to said subscriber station, said instruction signal causing said subscriber station to receive said interference time slot for a predetermined time period, and

wherein said subscriber station which has received said instruction signal receives said interference time slot for a predetermined time period, and when the interference disappears, said subscriber station sends a request to said base station, said request requesting a deletion of said interference time slot information registered into said interference time slot data.

9. The TDMA wireless communication system as claimed in claim 8, wherein an interference erroneous detection database is provided on the side of either the base station or the subscriber station, and the interference time slot information deleted from the interference time slot database is registered into said interference erroneous detection database.

10. The TDMA wireless communication system as claimed in claim 9, wherein when the same interference time slot information whose total number is larger than, or equal to a preselected number is registered into the interference erroneous detection database within a predetermined time period, an abnormal state is transmitted to a central station for managing the base station.

11. The TDMA wireless communication system as claimed in claim 9, wherein when the same interference time slot information whose total number is larger than, or equal to a preselected number is registered into the interference erroneous detection database within a predetermined time period, an interference judging threshold value used to detect interference is increased.