Cellular mobile base station apparatus

Abstract: A cellular mobile base station apparatus comprises a first plurality of transceivers operating in a first radio frequency range assigned to a first cell and receiving power from a first power supply unit, a second plurality of transceivers operating in a second radio frequency range assigned to a second cell and receiving power from the first power supply unit, a third plurality of transceivers operating in the first radio frequency range and receiving power from a second power supply unit, and a fourth plurality of transceivers operating in the second radio frequency range and receiving power from the second power supply unit. The outputs of the first and third pluralities of transceivers are combined and transmitted from first antenna and a signal in the first frequency range received by the first antenna is decomposed into first frequency range individual signals and applied to the first and third pluralities of transceivers. The outputs of the second and fourth pluralities of transceivers are combined and transmitted from a second antenna, and a signal in the second frequency range received by the second antenna is decomposed into and transmitted from a second antenna, and a signal in the second frequency range received by the second antenna is decomposed into second frequency range individual signals and applied to the second and fourth pluralities of transceivers.

Description: Field of the Invention The present invention relates generally to cellular mobile communication systems and more specifically to a base station apparatus of the system. Description of the Related Art As illustrated in Figs. 1 and 2, the base station apparatus of a conventional time-division multiple access (TDMA) cellular mobile communication system is comprised of a common control unit(1)which is connected to a mobile telephone switching office, not shown, to provide overall control of the base station. Common control unit (1) is powered by a power supply unit ( 2 )and mounted on an upper shelf ( 3 ) of the apparatus frame with the power supply unit ( 2 ). The base station serves two cells to which frequency ranges 1.5 GHz and 800 MHz, for example, are assigned respectively. To serve the 1.5-GHz range cell, a plurality of radio transceiver panels ( 4 ) are provided which are connected to the common control unit ( 1 ) and commonly powered by a power supply unit 5 . Each transceiver panel ( 4 ) has a bandwidth of 0.25 MHz in the 1.5-GHz range and three time slots are multiplexed in the 0.25 MHz band of each transceiver. The transceiver panels ( 4 ) and power supply unit( 5 ) are both mounted side by side on a middle shelf ( 6 ). The output terminal of each transceiver panel ( 4 ) is connected to a frequency division multiplexer ( 7A ) where it is multiplexed with the outputs of other transceivers and supplied to a diplexer ( 9A ) and transmitted from antenna ( 10A ). Signals from mobile units located in the 1.5-GHz range cell are received by antenna ( 10A ) and fed through diplexer ( 9A ) to a frequency division demultiplexer ( 8A ) where they are decomposed into individual frequency signals and supplied respectively to transceiver panels ( 4 ). To serve the 800-MHz range cell zone, a plurality of radio transceivers 14 are provided which are connected to the control unit 1 powered by a power supply unit 15 and mounted side by side on a lower shelf 16. Each transceiver panel 14 has a bandwidth of 0.25 MHz in the 800-MHz range and three time slots are multiplexed in the 0.25 MHz band of each transceiver. The output terminal of each transceiver panel 14 is connected to a frequency division multiplexer 7B where it is multiplexed with the outputs of other transceivers 14 and supplied to a diplexer 9B and transmitted from antenna 10B. Signals from mobile units located in the 800-MHz range cell zone are received by antenna 10B and fed through diplexer 9B to a frequency demultiplexer 8B where they are decomposed into individual frequency signals and supplied respectively to transceiver panels 14. The control unit 1 receives an incoming call from the MTSO and, in response, selects one of the transceivers and one of the time slots assigned to it, depending on the destination address of the incoming call, and operates the selected transceiver for transmission to a mobile station. In return, a signal sent from the mobile station is received through demultiplexer 8A by the selected transceiver and applied through control unit 1 to the MTSO. If any one of the power supply units 5 and 15 should fail, all transceivers powered by the failed power supply become inoperative and service breakdown occurs in the cell served by the failed transceiver. WO92/12579 describes a radio transceiver system comprising several transceivers belonging to respective radio systems, an antenna, and a filter connectable to the antenna for filtering signals applied to the antenna and received by the antenna. A dividing unit divides the signals received by the antenna to the different transceivers. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a base station apparatus which prevents the total service breakdown of a cell zone due to power failure. According to the present invention, there is provided a base station apparatus for a cellular mobile communication system in which different frequency ranges are assigned respectively to cell zones and the base station apparatus serves first and second cell zones, comprising a first power supply unit, a first plurality of transceivers operating in a first radio frequency range assigned to the first cell zone and receiving power from said first power supply unit, a second plurality of transceivers operating in a second radio frequency range assigned to the second cell zone and receiving power from said first power supply unit, a second power supply unit, a third plurality of transceivers operating in said first radio frequency range and receiving power from said second power supply unit, a fourth plurality of transceivers operating in said second radio frequency range and receiving power from said second power supply unit, first combining means for combining outputs of said first and third pluralities of transceivers and transmitting the combined outputs from a first antenna, first decomposing means for decomposing a signal in said first frequency range received by the first antenna into first frequency range individual signals and coupling the first frequency range individual signals to said first and third pluralities of transceivers, second combining means for combining outputs of said second and fourth pluralities of transceivers and transmitting the combined outputs from a second antenna, second decomposing means for decomposing a signal in said second frequency range received by the second antenna into second frequency range individual signals and coupling the second frequency range individual signals to said second and fourth pluralities of transceivers, and a control unit for monitoring said first and second power supply units, said control unit being connected to a mobile switching office responsive to receipt of an incoming call therefrom for making a search through all of said transceives for an idle transceiver when both of said power supply units are normally operating, making a search exclusively through said third and fourth pluralities of transceivers for an idle transceiver when said first power supply unit is known to have failed and making a search exclusively through said first and second pluralities of transceivers for an idle transceiver when said second power supply unit is known to have failed. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be described in further detail with reference to the accompanying drawings, in which: Fig. 1 is a block diagram of a prior art base station apparatus of a time-division multiple access cellular mobile communication system; Fig. 2 is a front view of a frame in which the prior art base station apparatus is mounted; Fig. 3 is a block diagram of a base station apparatus of a time-division multiple access cellular mobile communication system according to the present invention; and Fig. 4 is a front view of a frame in which the base station apparatus of the present invention is mounted. DETAILED DESCRIPTION Referring now to Figs. 3 and 4, there is shown a base-station apparatus of the present invention wherein parts corresponding to those in Figs. 1 and 2 are indicated by the same numerals as used in Figs. 1 and 2 and operate in the same manner as described previously. It is seen in Fig. 4 that on the middle shelf ( 6 )a group of 1.5-GHz range transceiver panels ( 34A ) and a group of 800-MHz range transceiver panels ( 34B ) are mounted side by side and on the lower shelf ( 16 ) a group of 1.5-GHz range transceiver panels ( 44A )and a group of 800-MHz range transceiver panels ( 44B ) are mounted side by side. All transceiver panels ( 34A ) and ( 34B ) on shelf ( 6 ) are commonly powered by the power supply unit ( 5 ) and all transceiver panels ( 44A ) and ( 44B ) on shelf ( 16 ) are commonly powered by the power supply unit ( 15 ). Each of the transceivers ( 34A ) and ( 44A ) has a bandwidth of 0.25 MHz in the 1.5 GHz range, and each of the transceivers ( 34B ) and ( 44B ) has a bandwidth of 0.25 MHz in the 800 MHz range. Three time slots are multiplexed into the 0.25-MHz band of each of the transceivers ( 34A ), ( 34B ), ( 44A ) and ( 44B ). With reference to Fig. 3, the outputs of all 1.5-GHz range transceivers (34A) and 44(A) are connected to frequency division multiplexer (7A), while the outputs of all 800-MHz range transceivers ( 34B ) and ( 44B ) are connected to frequency division multiplexer ( 7B ). The 1.5-GHz range signals received by antenna ( 10A ) are coupled through diplexer ( 9A ) to frequency division demultiplexer ( 8A ) where they are demultiplexed into individual frequency signals in the 1.5-GHz range. These 1.5-GHz time-slot signals are coupled respectively to the transceiver panels ( 34A ) on middle shelf ( 6 ) and transceiver panels ( 44A ) on lower shelf ( 16 ). On the other hand, the 800-MHz range signals received by antenna ( 10B ) are coupled through diplexer ( 9B ) to frequency division demultiplexer ( 8B ) where they are demultiplexed into individual frequency signals in the 800-MHz range, which are coupled respectively to the transceiver panels ( 34B ) on shelf ( 6 ) and transceiver panels ( 44B ) on shelf ( 16 ). Control unit ( 1 ) monitors the power supply units ( 5 ) and ( 15 ) to isolate those transceivers from the system whose associated power supply unit has failed. During normal operation, control unit ( 1 ) makes a search through all the transceivers on shelves ( 6 )and ( 16 ) for an idle one in response to receipt of an incoming call from the MTSO, not shown. If the power supply unit ( 5 ) should fail, all transceivers on shelf ( 6 ) become inactive, and control unit ( 1 ) isolates them from the system and makes a search exclusively through the transceivers on shelf ( 16 ) for an idle transceiver. Since the power supply unit ( 15 ) still supports the 1.5 GHz and 800 MHz range transceivers on shelf ( 16 ), total service breakdown of one of the cell zones is prevented.

Claims: A base station apparatus for a cellular mobile communication system in which different frequency ranges are assigned respectively to cell zones and the base station apparatus serves first and second cell zones, comprising: a first power supply unit (5); a first plurality of transceivers (34A) operating in a first radio frequency range assigned to the first cell zone and receiving power from said first power supply unit; a second plurality of transceivers (34B) operating in a second radio frequency range assigned to the second cell zone and receiving power from said first power supply unit; a second power supply unit (15); a third plurality of transceivers (44A) operating in said first radio frequency range and receiving power from said second power supply unit; a fourth plurality of transceivers (44B) operating in said second radio frequency range and receiving power from said second power supply unit; first combining means (7A) for combining outputs of said first and third pluralities of transceivers and transmitting the combined outputs from a first antenna (10A); first decomposing means (8A) for decomposing a signal in said first frequency range received by the first antenna into first frequency range individual signals and coupling the first frequency range individual signals to said first and third pluralities of transceivers; second combining means (7B) for combining outputs of said second and fourth pluralities of transceivers and transmitting the combined outputs from a second antenna (10B); second decomposing means (8B) for decomposing a signal in said second frequency range received by the second antenna into second frequency range individual signals and coupling the second frequency range individual signals to said second and fourth pluralities of transceivers; and a control unit (1) for monitoring said first and second power supply units, said control unit being connected to a mobile switching office responsive to receipt of an incoming call therefrom for making a search through all of said transceivers for an idle transceiver when both of said power supply units are normally operating, making a search exclusively through said third and fourth pluralities of transceivers for an idle transceiver when said first power supply unit is known to have failed and making a search exclusively through said first and second pluralities of transceivers for an idle transceiver when said second power supply unit is known to have failed. A base station apparatus as claimed in Claim 1, wherein said first and second pluralities of transceivers and said first power supply unit are mounted on a first shelf (6), and said third and fourth pluralities of transceivers and said second power supply unit are mounted on a second shelf (16).

Inventors: OHGAMI NAOTO, OHGAMI, NAOTO
Applicants: NIPPON ELECTRIC CO, NEC CORPORATION
Application year: 1993
Main classification: H04B7
IPC codes: H04B7, H04W88