Base transceiver station and subscriber unit in wireless local loop system using personal handy-phone system and method for operating same

• US 6,175,747 B1
• Filed: 03/20/1997
• Issued: 01/16/2001
• Est. Priority Date: 06/28/1996
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ishikawa, Hitoshi, Hamada, Yutaka, Mashima, Rikihiko, Sogo, Hiroyuki, Yamashita, Atsushi, Kubo, Tsudoi, Shirota, Masahiko, Tanishima, Yasuo, Seta, Mitsuru
• Primary Examiner(s): Bost, Dwayne D.
• Assistant Examiner(s): Persino, Raymond B.
• Application Number:
  US08/821,627
• Time in Patent Office: 1,398 Days
• Field of Search: 455/403, 455/561, 455/562, 455/82, 455/83, 455/13.3, 455/272, 455/342, 455/422, 455/445, 455/560, 455/446, 455/448, 455/464, 455/502, 455/503, 455/554, 455/466, 455/67.4, 455/72, 455/436, 455/277.1, 455/552, 370/336, 370/337, 370/347, 370/307, 370/222, 370/465
• US Class Current: 455/562.1
• CPC Class Codes: H04B 1/54 using the same frequency for two directions of communication H04B1/44 takes precedence
• CPC Class Codes: H04Q 11/0442 Exchange access circuits
• CPC Class Codes: H04Q 2213/13034 A/D conversion, code compression/expansion
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13162 Fault indication and localisation
• CPC Class Codes: H04Q 2213/13166 Fault prevention
• CPC Class Codes: H04Q 2213/13167 Redundant apparatus
• CPC Class Codes: H04Q 2213/13209 ISDN
• CPC Class Codes: H04Q 2213/13292 Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13298 Local loop systems, access network
• CPC Class Codes: H04Q 2213/13305 Transistors, semiconductors in general
• CPC Class Codes: H04Q 2213/1332 Logic circuits
• CPC Class Codes: H04Q 2213/13322 Integrated circuits
• CPC Class Codes: H04Q 2213/1334 Configuration within the switch

Abstract

A base transceiver station in a wireless local loop system using a personal handy-phone system constituted by a plurality of cell stations, each accommodating a plurality of subscriber units, a hybrid section integrally handling signals transmitted and received by the plurality of cell stations via a single antenna, and a multiplexing/demultiplexing unit integrally handling the signals transferred between the plurality of cell stations and an existing network, thereby enabling construction of a wireless local loop system which is small in size, can expand the service area without an increase of interference with other base transceiver stations, has a good affinity with existing networks, is provided with ISDN functions, and, at the same time, provides backup against faults and improves the transmission quality and reliability.

Claims

1. A base transceiver station in a wireless local loop system using a mobile communication system operated under a time division duplex (TDD) mode, comprising:

a plurality of cell stations for accommodating subscriber units each comprising a plurality of terminals and

a hybrid section comprising a multistage power combiner which is arranged between said plurality of cell stations and two transmitting and receiving antennas having a space diversity (SD) configuration and which combines the transmitting powers from the plurality of cell stations and feeds the combined power to one of said two transmitting and receiving antennas, a multistage power distributor which distributes the power received from one of said two transmitting and receiving antennas to said plurality of cell stations, a space diversity switch (SD·

SW) which combines said transmitting powers toward one of said two transmitting and receiving antennas, and a time division duplex (TDD) switch which alternately switches said one transmitting and receiving antenna between transmission use and reception use based on the time division duplex (TDD) mode,

said base transceiver station being provided with

a common transmitting amplifier which operates in a time division multiple access (TDMA) mode in which said plurality of cell stations occupy channels individually allocated for every time slot and which is provided on the output side of said multistage power combiner common to said plurality of cell stations, and

a common receiving amplifier provided on the input side of said multistage power distributor common with respect to said plurality of cell stations, and where

the base transceiver station further includes a bias changing means which gives a bias of a level in proportion to the number of said channels in use for every said time slot to at least one amplifier between said common transmitting amplifier and said common receiving amplifier.

3. A base transceiver station according to claim 1 or 2, wherein:

said base transceiver station is provided with a plurality of transmitting amplifiers for every plurality of said cell stations and where

the base transceiver station further includes a transmission gain changing means which detects said transmitting power at the point nearest the input end of said transmitting and receiving antenna and gives a transmission gain in accordance with the result of detection to said transmitting amplifiers.

4. A base transceiver station according to claim 3, wherein:

said base transceiver station operates in a time division multiple access (TDMA) mode in which said plurality of cell stations occupy channels individually allocated for every time slot and, at the same time, the plurality of cell stations operate while alternately repeating cycles of the transmission frame and reception frame as a whole based on said time division duplex (TDD) mode and where

said transmission gain changing means makes the transmitting amplifiers of said plurality of cell stations sequentially output a constant transmitting output measurement-use burst for every said time slot in each cycle of said reception frame to obtain the transmission gain in accordance with said detection result for every transmitting amplifier and gives the transmission gains to said transmitting amplifiers until the end of the cycle of the subsequent transmission frame.

5. A base transceiver station according to claim 1 or 2, wherein:

said base transceiver station is provided with a common transmitting amplifier which is provided on the output side of said multistage power combiner common to said plurality of cell stations and where

the base transceiver station further includes a transmission gain adjusting means which adjusts the transmission gain of the common transmitting amplifier so that the level of said transmitting output on the input end of said transmitting and receiving antenna is maintained at a value determined in correspondence with the number of the time slots being used in a state where the input level at the input end of said common transmitting amplifier becomes the same level for all of said plurality of cell stations.

2. A base transceiver station in a wireless local loop system using a mobile communication system operated under a time division duplex (TDD) mode, comprising:

a plurality of cell stations for accommodating subscriber units each comprising a plurality of terminals and

a hybrid section comprising a multistage power combiner which is arranged between said plurality of cell stations and a single transmitting and receiving antenna and which combines the transmitting powers from the plurality of cell stations and feeds the combined power to said transmitting and receiving antenna, a multistage power distributor which distributes the power received from said transmitting and receiving antenna to said plurality of cell stations, and a time division duplex (TDD) switch which alternately switches said transmitting and receiving antenna between transmission use and reception use based on the time division duplex (TDD) mode,

said base transceiver station being provided with

a common transmitting amplifier which operates in a time division multiple access (TDMA) mode in which said plurality of cell stations occupy channels individually allocated for every time slot and which is provided on the output side of said multistage power combiner common to said plurality of cell stations, and

a common receiving amplifier provided on the input side of said multistage power distributor common with respect to said plurality of cell stations, and where

the base transceiver station further includes a bias changing means which gives a bias of a level in proportion to the number of said channels in use for every said time slot to at least one amplifier between said common transmitting amplifier and said common receiving amplifier.

6. A base transceiver station in a wireless local loop system using a mobile communication system operated under a time division duplex (TDD) mode, comprising:

a plurality of cell stations for accommodating subscriber units each comprising a plurality of terminals and

a hybrid section comprising a multistage power combiner which is arranged between said plurality of cell stations and a single transmitting and receiving antenna and which combines the transmitting powers from the plurality of cell stations and feeds the combined power to said transmitting and receiving antenna and, a multistage power distributor which distributes the power received from said transmitting and receiving antenna to said plurality of cell stations, wherein

said base transceiver station is provided with

a common transmitting amplifier which operates in a time division multiple access (TDMA) mode in which said plurality of cell stations occupy channels individually allocated for every time slot and which is provided on the output side of said multistage power combiner common to said plurality of cell stations and

a common receiving amplifier provided on the input side of said multistage power distributor common with respect to said plurality of cell stations and where

the base transceiver station further includes a bias changing means which gives a bias of a level in proportion to the number of said channels in use for every said time slot to at least one amplifier between said common transmitting amplifier and said common receiving amplifier.

7. A based transceiver station in a wireless local loop system using a mobile communication system comprising a base transceiver station and a large number of fixed subscriber units which are distributed around the base transceiver station, are accommodated in the base transceiver station, and have a mobile terminal, wherein said base transceiver station determines a frequency to be used under a dynamic channel assign mode and is provided with a variably directional transmitting and receiving antenna means by which the transmitting and receiving wave is given a variable directivity in accordance with the distribution of said large number of fixed subscriber units with respect to said base transceiver station, and wherein said variably directional transmitting and receiving antenna means is fixedly operative in a directivity thereof once the distribution of said fixed subscriber units with respect to said base transceiver station is determined and the directivity is determined accordingly to match the determined distribution of the fixed subscriber units.

8. A base transceiver station according to claim 7, wherein:

said base transceiver station comprises a plurality of cell stations and operates under a time division multiple access (TDMA) mode in which the plurality of cell stations occupy channels individually assigned for every time slot and where

said variably directional transmitting and receiving antenna means, when grouping said large number of subscriber units for each direction seen from said base transceiver station and assigning the same time slot for all of the subscriber units belonging to the same group, imparts directivity oriented to each corresponding direction for respective time slots.

9. A base transceiver station according to claim 8, wherein:

said variably directional transmitting and receiving antenna means changes said directivity to omnidirectivity for every specific time slot for transferring control information between said base transceiver station and said subscriber units.

10. A base transceiver station according to claim 7, wherein said variably directional transmitting and receiving antenna means

has a dipole antenna and

a phase control unit which switches the difference in feeding phase to the dipole antenna for every said time slot.

11. A base transceiver station according to claim 7, wherein said variably directional transmitting and receiving antenna means comprises:

a first variably directional transmitting and receiving antenna unit and

a second variably directional transmitting and receiving antenna unit arranged at a right angle with respect to the first variably directional transmitting and receiving antenna unit.

12. A base transceiver station in a wireless local loop system using a “

personal handy-phone system”

(PHS) provided with;

a first base transceiver station including four cell stations each accommodating a plurality of subscriber units and a multiplexing/demultiplexing unit for multiplexing or demultiplexing digital signals transmitted and received between the cell stations and a subscriber exchange and

a second base transceiver station, combined as one body with said first base transceiver station, which includes four cell stations each accommodating a plurality of subscriber units and transmits and receives digital signals between the cell stations and said subscriber exchange by commonly using said multiplexing/demultiplexing unit in said first base transceiver station,

wherein in said first base transceiver station, one of said four cell stations is a master cell station handling control-use D-channel signals in addition to speech-use B-channel signals and the other three cell stations are slave cell stations transmitting and receiving the control-use D-channel signals by inter-processor communication with the master cell station; and

in said second base transceiver station, one of said four cell stations is a master cell station handling control-use D-channel signals in addition to speech-use B-channel signals and the other three cell stations are slave cell stations transmitting and receiving the control-use D-channel signals by inter-processor communication with the master cell station.

13. A base transceiver station according to claim 12, wherein

said multiplexing/demultiplexing unit comprises

a multiplexer/demultiplexer which demultiplexes the digital multiplex signal from the public switched telephone network (PSTN) side or multiplexes received signals into the digital multiplex signal to the public switched telephone network (PSTN) side and

a D-channel access control unit connected to this;

at said multiplexer/demultiplexer, a 30B+1D digital multiplex signal comprised of 30 B-channels (speech channels) and one D-channel (control channel) is separated into two B-channel systems comprising 3B×

1 channels and 4B×

3 channels and one D-channel system and

the separated 4B-channels are distributed to three said slave cell stations provided in said first base transceiver station and three said slave cell stations provided in said second base transceiver station and,

at the same time, the separated 3B channels are distributed to said master cell stations in said first and second base transceiver stations; and

said D-channel access control unit connects said D-channel system to the master cell station in said first base transceiver station and the master cell station in said second base transceiver station.

14. A base transceiver station according to claim 13, wherein:

said D-channel access control unit multiplexes a D-channel signal of a speed s from said master cell station in said first base transceiver station and a D-channel signal of a speed s from said master cell station in said second base transceiver station and

further multiplexes the same to a digital multiplex signal of a speed S (S>

s) to said public switched telephone network (PSTN) side via said multiplexer/demultiplexer.

15. A base transceiver station according to claim 13, wherein:

said D-channel access control unit converts a D-channel signal of a speed S obtained by demultiplexing from the digital multiplex signal on said public switched telephone network (PSTN) side by said multiplexer/demultiplexer to a first D-channel signal of a speed s and a second D-channel signal of a speed s and

distributes them to said master cell station in said first base transceiver station and said master cell station in said second base transceiver station.

16. A base transceiver station according to claim 13, wherein:

terminal endpoint identifiers (TEI) in a LAPD are fixedly allocated to said master cell station in said first base transceiver station and said master cell station in said second base transceiver station; and

said D-channel access control unit separates a D-channel signal of a speed S obtained by demultiplexing from the digital multiplex signal from said public switched telephone network (PSTN) side by said multiplexer/demultiplexer to a first D-channel signal of a speed s and a second D-channel signal of a speed s according to said terminal endpoint identifiers (TEI) and distributes them to said master cell station in said first base transceiver station and said master cell station in said second base transceiver station.

17. A base transceiver station according to claim 13, wherein:

said base transceiver station receives said digital multiplex signal obtained by placing the first D-channel signals oriented to said first base transceiver station and the second D-channel signals oriented to said second base transceiver station in a time slot for the D-channel according to a predetermined timing rule from said public switched telephone network (PSTN) side and

said D-channel access control unit automatically distributes the received first D-channel signals and second D-channel signals to said first base transceiver station and said second base transceiver station according to said predetermined timing rule.

18. A base transceiver station according to claim 17, wherein:

said time slot of the D-channel is divided into a plurality of blocks according to said predetermined timing rule, the first D-channel signals oriented to said first base transceiver station are allocated to the first block, the second D-channel signals oriented to said second base transceiver station are allocated to the second block, and the other blocks are regarded as empty blocks.

19. A base transceiver station according to claim 17, wherein:

when said base transceiver station receives said digital multiplex signal having a continuous frame configuration from said public switched telephone network (PSTN) side,

said predetermined timing rule is determined according to a repeatedly appearing series of frames;

the first D-channel signal oriented to said first base transceiver station is placed in said time slot of the D-channel in the first frame in one series of frames;

the second D-channel signal oriented to said second base transceiver station is placed in said time slot of the D-channel in the second frame; and

said time slots of the D-channel of the third frame and subsequent frames are regarded as idle time slots.

20. A base transceiver station according to claim 13, wherein:

said D-channel access control unit momentarily terminates said first and second D-channel signals of a speed s respectively received from said master cell station in said first base transceiver station and said master cell station in said second base transceiver station,

further multiplexes the same together with the monitoring control signal containing various monitoring control information generated in the base transceiver station, and

inserts the same as a D-channel signal of a speed S (S>

s) in the digital multiplex signal on said public switched telephone network (PSTN) side.

21. A base transceiver station according to claim 13, wherein:

when said base transceiver station receives a digital multiplex signal of a speed S obtained by multiplexing said first D-channel signal oriented to said master cell station in said first base transceiver station, a second D-channel signal oriented to said master cell station in said second base transceiver station, and monitoring control signal containing various monitoring control information used in the base transceiver station in the D-channel from said public switched telephone network (PSTN) side,

said D-channel access control unit terminates said first D-channel signal, said second D-channel signal, and said monitoring control signal, converts them to a first D-channel signal and second D-channel signal each having a speed s (S>

s), and transmits the same to the corresponding master cell stations.

22. A base transceiver station according to claim 13, wherein said D-channel access control unit manages and controls terminal endpoint identifiers (TEI) in a LAPD on said public switched telephone network (PSTN) side and the terminal endpoint identifiers (TEI) in a LAPD on each said master cell station side in said first and second base transceiver stations, replaces the terminal endpoint identifiers (TEI), and terminates the LAPD on said public switched telephone network (PSTN) side and the LAPD on each said master cell station side.

23. A base transceiver station according to claim 13, wherein said D-channel access control unit momentarily terminates download information of software which has been placed in said D-channel in said digital multiplex signal from said public switched telephone network (PSTN) side for transfer, holds this in its memory, and feeds the download information to said master cell stations in said first and second base transceiver stations by a LAPB protocol.

24. A base transceiver station in a wireless local loop system using a “

personal handy-phone system”

(PHS), wherein the base transceiver station is connected to a public switched telephone network (PSTN) via interface converting equipment converting a protocol used in the existing public switched telephone network (PSTN) and a protocol used in the wireless local loop system between each other, wherein said interface converting equipment has;

a first input/output unit connected to said wireless local loop system side;

a second input/output unit connected to said public switched telephone network (PSTN) side;

a switching unit inserted between said first input/output unit and the second input/output unit;

a layer 2 terminating unit for terminating digital data from said wireless local loop system side obtained via the switching unit and digital data of each layer 2 from said public switched telephone network (PSTN) side; and

a central processing unit (CPU) which processes the message of a layer 3 obtained at the layer 2 terminating unit, converts this to digital data of the layer 2 again, and transmits the resultant data to said public switched telephone network (PSTN) side and said wireless local loop system side opposing each other via said switching unit.

25. A base transceiver station according to claim 24, wherein said interface converting equipment further has

a maintenance and operating unit which performs at least monitoring and control of the interface converting equipment per se and said base transceiver station and management and maintenance of the subscriber information.

26. A method of operating a base transceiver station in a wireless local loop system using a “

personal handy-phone system”

(PHS) having

a first base transceiver station having a plurality of cell stations each accommodating a plurality of subscriber units and a multiplexing/demultiplexing unit for multiplexing or demultiplexing digital signals transmitted and received between the cell stations and a subscriber exchange, and

a second base transceiver station which has a plurality of cell stations each accommodating a plurality of subscriber units and commonly uses said multiplexing/demultiplexing unit in said first base transceiver station to transmit and receive digital signals between the cell stations and said subscriber exchange, wherein

at least one of said plurality of cell stations is set as the master cell station (CS1) handling control-use D-channel signals in addition to speech-use B-channel signals and the remaining plurality of cell stations are set as slave cell stations (CS2, CS3, and CS4) controlled by the master cell station; and

when a fault occurs in one said master cell station, the fault is covered by one of the remaining plurality of cell stations.

27. A method of operation according to claim 26, wherein:

when a fault occurs in the master cell station (CS1)in one of said first and second base transceiver stations each having said master cell station (CS1),

said base transceiver station is maintained by only the other of the first and second base transceiver stations.

28. A method of operation according to claim 26, wherein:

when a fault occurs in the master cell station (CS1) in one of said first and second base transceiver stations each having said master cell station (CS1),

said control, including that of said slave cell stations in that faulty base transceiver station, is continued by said master cell station in the other of the first and second base transceiver stations.

29. A method of operation according to claim 26, wherein:

a backup master cell station forming an active and standby pair together with the master cell station (CS1) is further added to said master cell station (CS1) and

when a fault occurs in the active master cell station (CS1), it is switched to said backup master cell station to continue said control.

30. A method of operation according to claim 26, wherein:

a universal cell station which can operate as said master cell station (CS1) and said slave cell stations (CS2, CS3, and CS4) is additionally provided and

when a fault occurs in one of said master cell station and said slave cell stations,

the function of the faulty cell station is taken over by the universal cell station.

31. A method of operation according to claim 26, wherein:

each of said slave cell stations (CS2, CS3, and CS4) is also provided with a function as said master cell station (CS1) and

when a fault occurs in said master cell station (CS1),

the function of the faulty master cell station (CS1) is taken over by a selected slave cell station.

32. A method of operation according to claim 31, wherein the slave cell station succeeding to function of the master cell station (CS1) is arbitrarily selected from among said plurality of slave cell stations (CS2, CS3, and CS4).

33. A method of operation according to claim 31, wherein:

second management information equivalent to first management information held by said master cell station (CS1) per se is held in a managing memory in said multiplexing/demultiplexing unit in parallel;

said selected slave cell station takes over said second management information from said managing memory; and

the entire base transceiver station is restarted.

34. A method of operation according to claim 31, wherein:

second management information equivalent to first management information held by said master cell station (CS1) per se is held parallelly in a common memory shared by all said cell stations;

said selected slave cell station takes over said second management information from said common memory; and

the entire base transceiver station in restarted.

35. A method of operation according to claim 31, wherein:

second management information equivalent to first management information held by said master cell station (CS1) per se is held in distributed memories provided in said slave cell stations (CS2, CS3, and CS4) in parallel;

said selected slave cell station takes over said second management information from its own distributed memory; and

the entire base transceiver station is restarted.

36. A method of operation according to claim 31, wherein:

when selecting said slave cell station to take over the function of said faulty master cell station;

a slave cell station where none of the channels are in use or, if there is no such cell station, the one of the cell stations having the smallest number of channels in use is selected from the plurality of slave cell stations (CS2 to CS4),

said selected slave cell station is restarted as the master cell station.

37. A method of operation according to claim 31, wherein:

when selecting said slave cell station to take over the function of said faulty master cell station,

a slave cell station where none of the channels are in use is searched for from among the plurality of slave cell stations (CS2 to CS4) and it is decided if there is not even one such slave cell station,

when the above decision has been made, one of the plurality of slave cell stations (CS2 to CS4) is arbitrarily selected as the new master cell station (CS1) and

the management information held by the new master cell station (CS1) at the time of selection is taken over by anyone of the other slave cell stations which were not selected.

38. A base transceiver station in a wireless local loop system using a mobile communication system operated under a time division duplex (TDD) mode, comprising:

a plurality of cell stations for accommodating subscriber units each comprising a plurality of terminals and

a hybrid section comprising a multistage power combiner which is arranged between said plurality of cell stations and two transmitting and receiving antennas having a space diversity (SD) configuration and which combines the transmitting powers from the plurality of cell stations and feeds the combined power to one of said two transmitting and receiving antennas, a multistage power distributor which distributes the power received from one of said two transmitting and receiving antennas to said plurality of cell stations, a space diversity switch (SD·

SW) which combines said transmitting powers toward one of said two transmitting and receiving antennas, and a time division duplex (TDD) switch which alternately switches said one transmitting and receiving antenna between transmission use and reception use based on the time division duplex (TDD) mode,

wherein said base transceiver station is provided with a plurality of transmitting amplifiers for every plurality of said cell stations and where

the base transceiver station further includes a transmission gain changing means which detects said transmitting power at the point nearest the input end of said transmitting and receiving antenna and gives a transmission gain in accordance with the result of detection to said transmitting amplifiers, said transmission gain is controlled by utilizing a reception cycle.

39. A base transceiver station in a wireless local loop system using a mobile communication system operated under a time division duplex (TDD) mode, comprising:

a plurality of cell stations for accommodating subscriber units each comprising a plurality of terminals and

a hybrid section comprising a multistage power combiner which is arranged between said plurality of cell stations and a single transmitting and receiving antenna and which combines the transmitting powers from the plurality of cell stations and feeds the combined power to said transmitting and receiving antenna, a multistage power distributor which distributes the power received from said transmitting and receiving antenna to said plurality of cell stations, and a time division duplex (TDD) switch which alternately switches said transmitting and receiving antenna between transmission use and reception use based on the time division duplex (TDD) mode,

said base transceiver station is provided with a plurality of transmitting amplifiers for every plurality of said cell stations and where

the base transceiver station further includes a transmission gain changing means which detects said transmitting power at the point nearest the input end of said transmitting and receiving antenna and gives a transmission gain in accordance with the result of detection to said transmitting amplifiers, said transmission gain is controlled by utilizing a reception cycle.