KR100289844B1 - Method for arranging channels between adjacent channels of broadband wireless local loop base station - Google Patents

Abstract

PURPOSE: A method for arranging channels between adjacent channels of a broadband wireless local loop base station is provided to reduce an interference between adjacent channels by efficiently assigning channels of frequency blocks to a plurality of sector, and by increasing the number of channels. CONSTITUTION: A channel bandwidth assigned to each sector in a cell is divided into an odd channel band and an even channel band and assigned in each sector. The band between adjacent channels is widely formed. Each odd and even channel band is combined as the unit of frequency block. After that, each odd and even channel band combined is assigned for being alternated to each center. The channel is assigned to each sector for maintaining an interval between the channel and the adjacent channel.

Description

Channel Arrangement Method between Adjacent Channels of Broadband Wireless Subscriber Network Base Station

The present invention relates to a channel arrangement method between adjacent channels of a broadband wireless subscriber network base station, and in particular, by efficiently allocating a channel of a frequency block to each cell and sector of the broadband wireless subscriber network to reduce interference between adjacent channels. The present invention relates to a channel arrangement method between adjacent channels of a subscriber station base station.

First, the Broadband Wireless Local Loop (B-WLL) system communicates in both directions using frequencies in the 24.25 to 24.75 GHz and 25.5 to 27.5 GHz bands, ie high radio frequencies above 20 GHz in the Ministry of Information and Communication Publication No. 1997-49. As a device capable of doing this, a device capable of providing a subscriber with a multimedia service as well as voice.

A wireless communication device for bidirectional communication using the radio frequency is composed of a base station and a subscriber device, and the base station simultaneously transmits and receives a plurality of radio channels transmitted and received from a plurality of subscriber devices. A base station system that processes multiple channels simultaneously consists of an antenna, a filter, a frequency converter, an amplifier, and the like, and a subscriber device communicates by occupying only a single transmission / reception channel among a plurality of wireless channels.

In this way, the broadband wireless subscriber network system for communicating the A-B, B-WLL band for the entire broadband wireless subscriber network (B-WLL) as shown in Fig. C, D frequency blocks and the A, B, C, D frequency blocks are the channels (a1, a2, ... an), (b1, b2, ... bn) of each frequency block,

divided into (c1, c2, ... cn), (d1, d2, ... dn), and the frequency blocks and channels divided as above are shown in FIG. Each of the sectors A, B, C, and D is divided into (b), (c) and (d), and each sector (a), (b) and (d) is shown in FIG. Channels (a1, a2, ... an), (b1, b2, ... bn), (c1, c2, ... cn) of the D frequency block,

(d1, d2, ... dn) are allocated respectively.

In the broadband wireless subscriber network (B-WLL) system, the channel bandwidth of each channel ai, bi, ci, di (i = 1,2, ..., n) is considered various bandwidths such as 20MHz, 30MHz, 40MHz, etc. The bandwidth of the system element for each sector is the bandwidth of each frequency block (A, B, C, D block).

However, the problem in the actual communication environment is that the frequency of the local oscillator between the transmission and reception changes by more than ± 5MHz due to the influence of the external temperature, so that a specific channel interferes with the adjacent channel during transmission and reception.

Therefore, in order to reduce the interference on the adjacent channel during transmission and reception, as shown in FIG. 4, the guard band (guard band) is placed in the 3 dB bandwidth between the specific channel (i) and the adjacent channel (i + 1) to cause frequency fluctuation ( However, the bandwidth used in consideration of the change) is used as the channel interval, but at this time, the number of available channels in the total bandwidth is reduced than when the 3dB bandwidth is used as the channel utilization.

An object of the present invention is to efficiently allocate a channel of a frequency block to a plurality of sectors in each cell in a broadband wireless subscriber network to increase the number of channels and to reduce interference between adjacent channels.

In order to realize the above object, the present invention allocates channels of frequency blocks per cell and sector of a broadband wireless subscriber network (B-WLL) system to each of the two frequency blocks (or a plurality of blocks) in each sector. It is characterized in that the channel is allocated across one another that is not adjacent.

1 is a general broadband wireless subscriber network frequency block and channel layout

2 is a cell and sector configuration diagram of a general broadband wireless subscriber station base station

3 is a frequency block and channel allocation diagram of a cell and a sector of a typical broadband wireless subscriber station base station.

4 is a diagram illustrating a relationship between a 3 dB channel bandwidth, a guard bandwidth, and a channel spacing of a general broadband wireless subscriber station;

5 is a frequency block and channel allocation diagram of cells and sectors of the present invention.

6 is a relation diagram of 3dB channel bandwidth, guard bandwidth and channel spacing of the present invention;

Explanation of symbols for main parts of the drawings

A, B, C, D block: frequency block a1, a2 ... an: A block, frequency channel

b1, b2 ... bn: B block, frequency channel c1, c2 ... cn: C block, frequency channel

d1, d2 ... dn: D block, frequency channel

5 is a frequency block and channel configuration diagram of a broadband wireless subscriber network base station of the present invention, in which channels of A, B, C, and D frequency blocks are allocated to each cell and sector of a broadband wireless subscriber network (B-WLL) system. , Odd channels of two A and B frequency blocks (a1, a3, a5, ..., b1, b3,

b5, ...) is allocated to one sector, and even channels (a2, a4, a6, ..., b2, b4, b6, ...) are assigned to the other sector (b), respectively. Assign. Similarly, odd channels (c1, c3, c5, ..., d1, d3)

, d5, ..) is allocated to one sector (c), and even channels (c2, c4, c6, ..., d2, d4, d6, ...) are allocated to one sector (d). Assign by skipping channels.

In other words, in the method of the present invention, the channel bandwidth allocated to each sector in the cell is divided into odd channel bands and even channel bands and allocated in sectors, so that the band i between adjacent channels is formed considerably wider than the conventional method. (i ±).

For example, assuming that any one channel in (a) is set to an odd number of 30 MHz by the method of the present invention, the remaining (b), (c) and (d) channels to be adjacent to each other may be held at minimum intervals. 10MHz or 50MHz will be allocated. Therefore, even if there is frequency influence of local oscillator, that is, frequency interference of ± 5MHz or more, there is at least 20MHz channel band between adjacent channels, so they do not overlap or cause interference.

In particular, the method of the present invention does not need to allocate one channel band to 3 (db) as in the conventional method, because the spacing between the channels is relatively wide. It can be seen that the interval is increased more than twice as shown in FIG.

Therefore, in the present invention, the channel spacing can be kept wide by allocating non-adjacent channels, i.e., across one channel, to the sectors of each cell of the broadband wireless subscriber network (B-WLL) system. The channel spacing can be maintained larger than the 3 dB bandwidth plus the guard bandwidth considering this frequency fluctuation, thereby reducing the adjacent channel interference of the transceiver. Also, each base station can expand the utilization by the number of channels divided by the total frequency bandwidth by the 3 dB bandwidth. Will be.

As described above, in the present invention, when allocating channels of a plurality of frequency blocks to sectors of each cell of a broadband wireless subscriber network (B-WLL) system, odd channels of two frequency blocks are allocated to one sector, The even channel is allocated to another sector across one channel, so that the channel spacing between the adjacent channels is widened by one channel to maintain a wider channel spacing between adjacent channels than the channel spacing of the conventional method. Can be reduced. In addition, in the base station, if the channel interval is 3dB bandwidth, the method can be used according to the method of the present invention, and the total frequency bandwidth can be utilized by the number of channels divided by the 3dB bandwidth, thereby maximizing the frequency utilization, and the channel interval of each sector is twice the 3dB bandwidth. Thus, the channel spacing can still be kept wide enough to prepare for adjacent channel interference. The bandwidth of system elements in a short sector is doubled compared to the general method.

Claims (1)

In a broadband wireless subscriber network (B-WLL) system, which allocates a channel per sector within a plurality of cells, The channel bandwidth (i) allocated to each sector of the cell is divided into an odd channel band and an even channel band, and a plurality of combinations of the odd channel and the even channel in frequency blocks are allocated alternately to each center. The allocated channel (i) in the channel allocation method for adjoining adjacent broadband channels, characterized in that the channel is allocated so as to maintain the interval between the adjacent channel and always (i ± 2) channel.

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