JP2004515110A - Traffic estimation apparatus in multi-sector antenna system of mobile communication system - Google Patents

Abstract

The present invention relates to a traffic estimating apparatus for a multi-sector antenna system of a mobile communication system, which receives multiple beams via an array antenna having N antenna cells (multiples of 4) for each sector. Such a traffic estimator samples the power of each multiplex beam received via the array antenna, calculates the average power of each multiplex beam, and calculates the traffic on each beam based on the difference between the calculated average powers. In order to estimate and distribute all multiplexed beams equally, beam switching control is performed according to each estimated traffic.

Description

[0001]
1. TECHNICAL FIELD The present invention relates to an apparatus for estimating traffic on multiple beams or multiple sectors using received signal power of a reverse link in a multi-sector antenna system of a mobile communication network.
[0002]
2. BACKGROUND ART In a mobile communication system, mobile communication base stations (BTS) are classified into 'omni' base stations and 'sector' base stations. However, most base stations are of the sector base station type. In a sector type base station (BTS), its service area is divided into three sectors or six sectors. A sector type BTS in a CDMA base station generally has three sector base stations.
[0003]
A sector-type BTS uses an antenna having a fixed beam width for each sector. Therefore, the geographical range of the service area of the sector is fixed. However, since traffic is usually unbalanced between BTS sectors, sufficient frequency resources are allocated to the sector that processes the largest traffic. As a result, the efficiency of frequency resources is reduced in a sector with a small amount of traffic, and the radio channel efficiency is reduced in a sector with a large concentration of traffic, thereby reducing the coverage. This causes problems such as a decrease in service efficiency and an increase in frequency resource management / maintenance costs in a BTS having a traffic imbalanced sector.
[0004]
Further, if the traffic load distribution changes between three sector base stations in a BTS with sectors each having a fixed service area, such situations are handled manually. That is, the operator suitably changes the direction of the antenna provided on the tower in order to adapt the change in the traffic load distribution. However, such a manual operation is not only extremely dangerous and troublesome, but also takes a long time to adjust the antenna. As a result, manual maintenance is inefficient.
[0005]
In order to solve such a problem, a multi-sector antenna system has been proposed in which each service area of a sector is variable based on the traffic load of each sector. In order to realize such a multi-sector antenna system, a traffic monitoring or estimating technique is necessarily required. However, the traffic monitoring or estimation techniques that have been proposed to date have a number of problems when applied to physical systems.
[0006]
Since conventional traffic estimation techniques had to estimate traffic indirectly based on the signal power of the forward link and combine it with the hardware of the operator's BTS, these have complex hardware structures. They are necessary and inefficient from a cost standpoint, and their estimation performance is not good.
[0007]
In particular, these problems are very pronounced in multi-sector antenna systems using array antennas each emitting a plurality (eg, four or eight beams). Therefore, there is an urgent need for a multi-beam traffic estimation technique that allows each antenna element to estimate traffic.
[0008]
3. DISCLOSURE OF THE INVENTION An object of the present invention is to receive individual signal powers input from multiple beams and estimate the traffic of each beam or sector based on each received signal power in a multi-sector antenna system that radiates multiple beams. It is an object of the present invention to provide a multi-beam or multi-sector traffic estimating apparatus which can be executed separately from a BTS.
[0009]
A traffic estimating apparatus in a multi-sector antenna system according to the present invention comprises: a power sampling module for sampling signal power of each of N beams received from an array antenna; and N signal powers from the power sampling module at predetermined intervals. An N: 1 switching module for sequentially selecting; a filtering / amplifying module for converting a series of power outputs from the N: 1 switching module into respective signals of a predetermined frequency band and amplifying the signals appropriately; A power detection module for converting the power of each signal sequentially output from the N-channel into a voltage value; comprising a timing clock required for a series of input selections of an N: 1 switching module, and calculating respective averages of the respective voltage values And use the calculated average It is characterized in that consisting of: and, system control module for estimating the traffic on each beam or each sector.
[0010]
With a multi-beam or multi-sector traffic estimator whose structure is very simple, the cost of installation and maintenance is significantly reduced, the performance of the traffic estimation is further improved, and an improved traffic estimation for each beam or sector is achieved. A traffic balance between all the sectors is achieved via, so that the use of frequency resources can be efficient.
[0011]
5. BEST MODE FOR CARRYING OUT THE INVENTION In order to fully understand the present invention, preferred embodiments will be described below with reference to the accompanying drawings.
[0012]
In the embodiment of the traffic estimating apparatus in the multi-sector antenna system of the mobile communication network according to the present invention, all service areas of the BTS are divided into three (= K) sectors, and four or eight (= M) sectors are provided. It is assumed that an array antenna that emits the same beam is used for each sector. Thus, embodiments of the present invention estimate traffic for each beam or sector based on a total of K × M, or 12 (or 24), individual received signal powers.
[0013]
FIG. 1 is a block diagram of a traffic estimation device in a multi-sector antenna system that radiates K × M beams according to the present invention. 1 includes a K array antenna 100; a power sampling module 102; an N: 1 switching module 104 (where N = K × M); a filtering / amplifying module 106; and a power detection module 110.
[0014]
As shown in FIG. 1, the power sampling module 102 samples all N beams received from the K array antennas 100, each emitting M beams. The power sampling module 102 can be realized by a 20 dB directional coupler. The N: 1 switching module 104 sequentially selects N sampled outputs from the power sampling module 10 at predetermined intervals, and sequentially outputs according to a selection command. A timing clock requesting selection of a periodic interval of the N: 1 switching module 104 is provided in the system control module 110.
[0015]
The filtering / amplifying module 106 performs a function of converting a series of power output from the N: 1 switching module 104 into a desired frequency band and respective signals, and amplifying the signals appropriately.
[0016]
The power detection module 108 converts the power of each signal sequentially output from the filtering / amplification module 106 into a voltage value, and sequentially transmits the converted value to the next system control module. The power detection module 108 can change its original cutoff frequency to a suitable frequency between 1 and 10 KHz in order to estimate relatively high-frequency noise mixed in the signal processing or the preceding process. . The power detection module 108 has a capacitor filter (not shown) whose function is to estimate noise as described above. A detailed description of such a capacitor filter will be omitted because it is obvious to a person skilled in the art.
[0017]
The system control module 110 classifies the voltage values received from the power detection module 108 according to the beam or sector, and calculates an average of the voltage values stored so far for each beam or sector. From the average of each calculated voltage value, the average of the traffic of each beam or sector is estimated. After estimating each traffic, the system control module 110 also evaluates how the traffic is imbalanced between beams or sectors.
[0018]
In addition, the system control module 110 also generates a multi-channel control signal that is supplied to the N: 1 switching module 104, synchronized with the timing clock. The multi-channel control signal is used for the reception power detection, transmission, classification and storage process of each beam for synchronization between internal or combining operations.
[0019]
The system control module 110 further performs beam switching control of multiple beams based on the estimated average traffic for each beam or sector (or the estimated traffic difference between beams or sectors). That is, a beam splitting / combining control signal is generated to distribute traffic evenly among the K sectors. Uniform distribution of traffic between sectors is achieved through the modification or redistribution of one or more beams to other sectors where traffic is relatively concentrated according to beam splitting / combining control signals.
[0020]
The traffic estimation apparatus described above is implemented as a subsystem of a BTS having a sector variable multiplex beam, but can also be applied to other systems such as a switching smart antenna system.
[0021]
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
[Brief description of the drawings]
4. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention, illustrate preferred embodiments of the invention, together with the description, and are provided to explain the principles of the invention.
FIG.
FIG. 1 is a block diagram of a traffic estimation device in a multi-sector antenna system of a mobile communication network according to the present invention.

Claims (5)

A power sampling module for sampling the signal power of each of the N beams received from the array antenna;
An N: 1 switching module for sequentially selecting N signal powers from the power sampling module at predetermined intervals;
A filtering / amplifying module for converting a series of power outputs from the N: 1 switching module into respective signals in a predetermined frequency band and suitably amplifying the signals;
A power detection module that converts the power of each signal sequentially output from the filtering / amplification module into a voltage value;
Comprising a timing clock required for a series of input selections of the N: 1 switching module, calculating respective averages of said respective voltage values, and using said calculated average values for each beam or each sector. A system control module for estimating traffic;
An apparatus for estimating traffic in a multi-sector antenna system of a mobile communication system, comprising: The traffic estimation device according to claim 1, wherein the power sampling module is realized by a directional coupler. The traffic estimation device according to claim 1, wherein the power detection module has a cutoff frequency for estimating noise mixed into received signal power. The traffic estimation device according to claim 3, wherein the cutoff frequency is in a range of 1 KHz to 10 KHz. The system control module further outputs a signal to control an individual sector distribution of the N beams based on the estimated traffic on each beam or each sector. Item 2. The traffic estimation device according to item 1.

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