JPH0955977A - Channel allocation method for radio base station having sector antenna - Google Patents

Abstract

(57) [Abstract] [Problem] To enable channel segregation for sector cells. A plurality of sectors 22 _{1 to} 22 _n of a sector antenna of a base station are sequentially switched and connected to a transmission / reception unit 12, and channel priority memories 25 _{1 to} 25 _n are provided for the respective sectors 22 _{1 to} 22 _n. Any sector 22k
Memory 25 corresponding to the call of the mobile station of the sector cell of
Search for and allocate empty channels in order of priority from k,
Moreover, the priority of the channel is raised and the memory 25k is rewritten.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention configures a sector (fan-shaped) cell by a radio base station having a sector antenna,
The present invention relates to a method of allocating a channel used for communication to a mobile station in a radio base station of mobile communication which covers a service area with a plurality of sector cells.

[0002]

2. Description of the Related Art Conventionally, a radio base station normally having an omnidirectional antenna constitutes a circular zone (cell) (omni cell) having the base station as a center, and a plurality of the omni cells covers a service area. are doing. In each base station, a channel is allocated every time a call occurs in order to communicate with a mobile station in the cell to which it belongs.
The frequency band used in mobile communication is predetermined,
In order to effectively use that frequency, channels of the same frequency are used in cells that are far apart from each other so as not to interfere with each other. It is repeatedly used locally. Channels usable in each cell are fixedly allocated, but the optimum allocation needs to measure the degree of channel interference in each cell according to the entire service area.
It requires a lot of work.

In addition, all channels are made available in each cell so that the channels can be effectively used, and each base station autonomously allocates a used channel to a mobile station, and while repeating the allocation, each cell A channel segregation method has been proposed in which the channels used in are almost constant (eg, Furuya et al., “Channel segr”).
eg, a distributed ada
ptive channel allocation
scheme for mobile communi
"Cation systems" IEICE Tran
s, vol. E74, pp. 1531-1537, Ju
ne 1991).

In this system, a base station has an omnidirectional antenna 11 as shown in FIG.
, And the modulator / demodulator 13 is connected to the transmitter / receiver 12, and the modulator / demodulator 13 is time-division multiple access control (TDMA unit).
14 is connected, and the TDMA unit 14 is connected to the converter via the interface 15 and the communication line. In order to generate a call and allocate a communication channel to the call, the channel control unit 16 refers to the channel priority memory 17 to read out a channel having a higher priority from the empty channels, and to set the frequency of the channel to the transmission / reception unit 12. , And the time slot of the channel is designated and set in the TDMA unit 14. This allows the mobile station (not shown) to communicate with this base station through the channel.

When the channel is assigned, the priority of the channel in the cell is increased, and the reception level of the idle channel is periodically measured by the level measuring unit 18, so that the priority of the interfering channel is lowered. The channel priority is changed from time to time using the learning function. By doing this, the channels used preferentially in this base station are automatically divided for each base station, and all channels can be used due to traffic fluctuations, etc., and the channels are used efficiently. Moreover, it is not necessary to manage the channel allocation in one place.

[0006]

In recent years, large-capacity, wide-band communication including moving images has been required in multimedia communication, and quality deterioration due to multipath is prevented during wireless transmission of a wideband signal to obtain good communication quality. For this purpose, a sector antenna using a directional antenna is effective, that is, it is desired to cover the service area with a plurality of sector cells. By dividing the omni cell covered by the omnidirectional antenna into a plurality of sector cells by a plurality of sector antennas, it is possible to further avoid interference between cells.

No method has been proposed for efficiently performing distributed autonomous channel allocation in each base station when the service area is covered by such a sector cell.

[0008]

According to the present invention, a channel priority memory corresponding to a sector cell is provided, and an empty channel is assigned in accordance with the priority order stored in the channel priority memory. According to a second aspect of the present invention, in the first aspect of the present invention, the sector antenna has a plurality of sectors, and transmission / reception is performed with a radio base station by switching between a mobile station and a sector in each sector cell corresponding to each sector. Then, a channel priority memory is provided for each sector cell, and channel allocation to mobile stations in each sector cell is performed by referring to the channel priority memory of the sector cell.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the invention of claim 2 and parts corresponding to those of FIG. In this embodiment, the radio base station is provided with a sector antenna 21, and the sector antenna 21 has a plurality of sectors 22 _{1 to} 22 _n.
The a, the wireless base station around the angularly divided n pieces of sector cells are respectively covered by sector 22 ₁ through 22 _n. These sectors 22 _{1 to} 22 _n are switched and connected to the transmission / reception unit 12 by a changeover switch 23. Under the control of the antenna switching / channel control unit 24, the sectors 22 _{1 to} 22 _n are sequentially transmitted one by one to the transmission / reception unit 12.
Switched to and connected. For each switching connection to each sector, the transmission / reception unit 12 is set to specify the channel frequency and the TDMA unit 14 is set to specify the time slot.

In this embodiment, each sector 22₁~ 2
2_nCorresponding to n sector cells defined by
Each channel priority memory 25₁~ 25_nIs provided
It For example, movement within a sector cell corresponding to sector 22k
Channel priority for assigning channels to stations
Search free channels in memory 25k in descending order of priority
26k, which is determined to be usable_pDivide
Hit The transmission / reception unit 12 is connected to the sector 22k, and
When connecting to a mobile station, the control unit 24
26k_pThe frequency designation setting of the
And channel 26k _pTime slot of the TDMA unit 14
Specify and set to. For mobile stations, channel 26k_p
In the channel priority memory 25k when
Channel 26k_pRewriting to raise the priority of
To be done. It should be noted that an empty channel is periodically set for each sector cell.
To receive channel priority memory 25₁~ 25_nCorrespondence of
However, the channel priority should be corrected.
Can also be.

FIG. 2 shows an embodiment of the invention of claim 3 and parts corresponding to those of FIG. 1 are designated by the same reference numerals. In this embodiment, a plurality of modulators / demodulators 13 _{1 to} 13 _m are provided, and one sector can simultaneously use a plurality of channels having different frequencies. Therefore, for example, sector 22k
According to the channel priority memory 25k corresponding to, the channel 26k _p is assigned to one call in accordance with the priority order, and when the next call is generated in the cell of the sector 22k while this communication is not completed, the memory 25k , The next available free channel 26k _q is assigned.

The modulator / demodulators 13 _{1 to} 13 _m are the transmitter / receiver 1
2 through may be connected to one or more with any of the sectors 22 ₁ through 22 _n. When a plurality of modulators / demodulators 13 _{1 to} 13 _m are used in this way, a channel priority memory is provided for each of the sectors 22 _{1 to} 22 _n as shown in FIG. 3, and each of the modulators / demodulators 13 _{1 to} 13 _m is provided. You can also

In the above description, one radio base station serves a plurality of sector cells, but one radio base station may be provided for each sector cell.

[0014]

As described above, according to the present invention, by providing the channel priority memory for each sector cell, the frequency utilization factor is increased by using the sector antenna, and the channel population is controlled by the distributed autonomous control. Be seen.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a radio base station to which the invention of claim 2 is applied.

FIG. 2 is a block diagram showing a configuration example of a radio base station to which the invention of claim 3 is applied.

FIG. 3 is a diagram showing a configuration example of a channel priority memory in a radio base station to which the invention of claim 4 is applied.

FIG. 4 is a block diagram showing a radio base station in which channel segregation is performed in a conventional omni cell.

Claims (5)

[Claims] 1. A channel allocation method for a mobile station in a sector cell which a radio base station having a sector antenna can transmit and receive through the sector antenna, wherein a channel priority memory corresponding to the sector cell is provided and stored in the channel priority memory. A channel allocation method for a wireless base station having a sector antenna, characterized in that an empty channel is allocated in accordance with the order of priorities. 2. The channel allocation method according to claim 1, wherein the sector antenna has a plurality of sectors, and the mobile station in each sector cell corresponding to each sector and the radio base station by switching the sector. A sector antenna, which is adapted to perform transmission / reception, is provided with the channel priority memory for each sector cell, and performs channel assignment to a mobile station in each sector cell by referring to the channel priority memory of the sector cell. A channel allocation method for a wireless base station having the following. 3. The channel allocating method according to claim 2, wherein one modulator / demodulator is switched and used, and a channel allocating method for a radio base station having a sector antenna. 4. The channel allocation method according to claim 2, wherein a plurality of modulators / demodulators are provided so that channels of different frequencies can be simultaneously used. 5. The channel allocation method according to claim 4, wherein the channel priority memory is provided for each modulator / demodulator, and the channel allocation method for a radio base station having a sector antenna.