KR100690113B1 - Apparatus for counting repeating service call in orthogonal frequency division multiple access system - Google Patents

Abstract

The relay service call counting apparatus according to the present invention converts a downlink signal transmitted from a base station into a baseband signal, detects downlink control information from the downlink baseband signal, and includes an uplink part included in the downlink control information. Detect channel assignment information. In addition, after converting an uplink signal transmitted from the terminal to a baseband signal, the uplink subchannels are separated from the uplink baseband signal based on the uplink subchannel allocation information, and the subchannels are relayed by the repeater. Detect the channel. The number of subchannels detected as such is counted as the number of calls being relayed by the repeater. Accordingly, the load of the repeater can be determined.

Orthogonal Frequency Division Multiple Access (OFDMA), Repeater, Call Counting.

Description

Relay service call counting device for orthogonal frequency division multiple access system {APPARATUS FOR COUNTING REPEATING SERVICE CALL IN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM}

1 is a block diagram of a conventional OFDMA / TDD system,

2 is a diagram illustrating a conventional OFDMA / TDD downlink frame and uplink frame structure;

3 is a block diagram of an apparatus for relaying service call counting according to an embodiment of the present invention;

4 is a block diagram of a downlink control signal analyzer according to an embodiment of the present invention;

5 is a block diagram illustrating a service subchannel detector according to an embodiment of the present invention;

6 illustrates an uplink frame illustrating an example in which a subchannel is allocated to each terminal.

The present invention relates to an Orthogonal Frequency Division Multiple Access (OFDMA) system, and more particularly to an apparatus for counting calls being relayed to measure the load of repeaters in an OFDMA system.

The OFMDA system provides broadband access with high speed portable Internet access and multimedia services. The OFDMA service provider needs to determine the installation and removal of the base station or repeater according to the load level by measuring the load of the base station or repeater in order to improve the quality of service.

In the case of the base station, communication with the exchange is directly performed, and the inside of the base station can share and process information of higher layers, thereby easily implementing a call counting function that can measure the load. The call counting function means a function of measuring a load by counting a call being serviced.

However, the repeater only performs a simple relay function that amplifies the base station signal and transmits it to the terminal and amplifies the terminal signal to the base station.

Accordingly, the present invention provides an apparatus capable of counting calls in relay service in a repeater.

Relay service call counting apparatus of the present invention for this purpose, a downlink signal converter for converting a downlink signal transmitted from a base station into a baseband signal, and detects the downlink control information from the downlink baseband signal and downlink A downlink control signal analyzer for detecting uplink subchannel allocation information included in the control information, an uplink signal converter for converting an uplink signal transmitted from a terminal into a baseband signal, and an uplink subchannel allocation A service subchannel detector which separates uplink subchannels from the uplink baseband signal based on the information and detects subchannels being relayed by the repeater among the subchannels, and relays the number of service subchannels by the repeater And a call counter that counts as the number of calls.

In addition, the relay service call counting method of the present invention includes a downlink signal conversion step of converting a downlink signal transmitted from a base station into a baseband signal, detecting downlink control information from the downlink baseband signal, and applying the downlink control information to the downlink control information. A downlink control signal analysis step of detecting uplink subchannel allocation information included; an uplink signal conversion step of converting an uplink signal transmitted from a terminal into a baseband signal; and based on uplink subchannel allocation information A service subchannel detection step of separating uplink subchannels from an uplink baseband signal and detecting subchannels being relayed by a repeater among the subchannels, and the number of service subchannels as the number of calls being relayed by the repeater. And a call counting step of counting.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the annexed drawings, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted. In addition, in the following description, an example in which the present invention is applied to a system employing the OFDMA / TDD (Time Division Duplex) scheme in the OFDMA scheme is given.

1 is a configuration diagram of an OFDMA / TDD system including a repeater, and shows a basic configuration of a conventional OFDMA / TDD. In FIG. 1, for convenience, one terminal 104 is serviced from the base station 100 through one repeater 102, but typically, a plurality of repeaters are connected to one base station 100. The repeater provides a relay service for a plurality of terminals.

The base station 100 transmits a downlink frame to the repeater 102 using a wire 106 such as an optical cable or a radio 108 interface of RF (Radio Frequency). After receiving the downlink frame, the repeater 102 transmits the downlink frame to the terminal 104 using the RF interface 110 in accordance with the TDD after detecting the TDD synchronization signal. After the terminal 104 receives the required downlink frame, the terminal 104 transmits the uplink frame to the repeater 102. The repeater 102 receiving the uplink frame transmits the uplink frame to the base station 100 using the wire 106 or the RF interface 108.

For reference, the frame structure of the OFDMA / TDD scheme is shown in FIG. 2. The downlink frame consists of the preamble 200, the downlink control data 202, and the downlink traffic data 204. The preamble 200 is used to extract the TDD synchronization of the repeater and the terminal and channel estimation and other base station related information from the terminal. The downlink control data 202 includes information on the structure of the downlink frame and the uplink frame as downlink control information. Downlink traffic data 204 is actual traffic data. The uplink frame also includes uplink control data 206 and uplink traffic data 208.

3 is a block diagram of a relay service call counting apparatus according to an embodiment of the present invention, and shows an example applied to an RF repeater. In the case of an optical repeater, the remaining parts except for the antenna and the TDD switch 300 are equally applied.

The OFDMA / TDD repeater including the relay service call counting apparatus of FIG. 3 first receives the downlink signal of RF from the base station and converts the downlink signal to the baseband signal by the downlink signal converter 302. The TDD sync detector 312 detects the TDD sync signal from the downlink signal converted into the baseband signal, and then controls the TDD switch 300 to receive the downlink signal and the uplink signal separately according to the TDD signal.

In this state, the downlink control signal analyzer 304 detects downlink control information from the downlink control data 202 region of the downlink baseband signal as shown in FIG. 2, and is included in the downlink control information. Uplink subchannel allocation information is detected and provided to the service subchannel detector 308.

Referring to FIG. 4, which shows a block diagram of the downlink control signal analyzer 304, the downlink baseband signal converted to the baseband by the downlink signal converter 302 may be an FFT (Fast Fourier Transform) device (FFT). FFT) converts the time domain signal into a frequency domain signal. The time domain signal is converted into the frequency domain signal because the information of the OFDMA / TDD signal can be detected in the frequency domain. The downlink signal converted into the frequency domain is applied to the downlink frame control header (FCH) / UL-MAP (uplink map) detection / demodulator 402.

The FCH / UL-MAP detection / demodulator 402 demodulates FCH information and UL-MAP information by detecting downlink FCH and UL-MAP regions from the downlink frequency domain signal. The uplink subchannel allocation information detector 404 detects uplink subchannel allocation information from the FCH information and the UL-MAP information demodulated by the FCH / UL-MAP detection / demodulator 402.

The uplink subchannel allocation information indicates how subchannels, that is, data burst intervals, are allocated to respective terminals serviced by the base station 100 in the uplink traffic data 208 region shown in FIG. Information to indicate. In the uplink frame as shown in FIG. 2, the subchannels are allocated to all terminals serviced by the base station 100, and thus the base station 100 as well as the repeater including the relay service call counting device shown in FIG. Also included is a subchannel allocated to a terminal on which a relay service is provided by another repeater connected to the network.

Referring to FIG. 3 again, in the uplink period, the OFDMA / TDD repeater receives an uplink signal of RF and converts it to a baseband signal by the uplink signal converter 306. The uplink signal converted to baseband is applied to the service subchannel detector 308. The service subchannel detector 308 separates the uplink subchannels from the uplink baseband signal based on the uplink subchannel allocation information provided from the downlink control signal analyzer 304, and the corresponding subchannel among the separated subchannels. Detects the subchannel during the relay service, that is, the service subchannel. The corresponding repeater is a term used to distinguish one repeater from other repeaters among repeaters connected to one base station.

Referring to FIG. 5 showing the block diagram of the service subchannel detector 308, the uplink baseband signal converted into the baseband by the uplink signal converter 306 is FFT by the FFT unit 500. Convert from time domain signal to frequency domain signal. The uplink signal converted into the frequency domain is applied to the uplink subchannel separator 502.

The uplink subchannel separator 502 then separates the uplink subchannels from the uplink frequency domain signal based on the uplink subchannel allocation information provided from the downlink control signal analyzer 304. The subchannel energy detector 504 detects the energy of each of these separated subchannels.

The comparator 506 then compares the energy of each of the subchannels with a preset threshold to detect a subchannel having energy above the threshold as the service subchannel. That is, the subchannels which are relayed by the corresponding relay are detected among the subchannels allocated to the uplink frame. Among the subchannels allocated to the uplink frame, the subchannel having energy below the threshold corresponds to a subchannel allocated to a terminal in relay service by another repeater, that is, another terminal outside the relay service range of the repeater. Therefore, the threshold is set in consideration of the range of energy values that the uplink signal corresponding to the subchannel allocated to the terminal within the relay service range of the relay among the subchannels may have.

As described above, the call counter 310 of FIG. 3 counts the number of service subchannels detected by the service subchannel detector 308 as the number of calls in the relay service by the corresponding repeater.

That is, the relay service call counting function according to the present invention uses a subchannel allocated to the uplink traffic data region 208 of FIG. 2 having a two-dimensional structure of frequency and time as shown in FIG. 6 using uplink information. Energy is detected for each time, and subchannels above a threshold are detected as service subchannels, and the number of detected service subchannels is counted. In the example of FIG. 6, three terminals corresponding to user bursts 2, 4, and 5 are relayed by corresponding relays in a state in which user bursts 1 to 5 are allocated to terminals as subchannels for five terminals in an uplink frame. Demonstrating receiving service. That is, an example in which three subchannels corresponding to user bursts 2, 4, and 5 are detected as service subchannels is shown.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications may be made within the scope of the present invention. In particular, the embodiment of the present invention shows an example of applying the present invention to an OFDMA / TDD system, but also applies to an OFMDA / FDD (Frequency Division Duplex) system. In addition, although the example is applied to the RF repeater, the same applies to the optical repeater. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be defined by the equivalents of the claims and claims.

As described above, the present invention separates uplink subchannels using subchannel allocation information for an uplink frame, and then compares the energy of each uplink subchannel with a threshold to determine the number of subchannels having energy above the threshold. By counting as a call being relayed by the repeater, the load of the repeater can be determined. As a result, it is possible to install more repeaters in high-load service areas and reduce the number of repeaters in low-load service areas.

Claims (4)

An apparatus for counting calls relayed by a repeater of an orthogonal frequency division multiple access system, the apparatus comprising: A downlink signal converter for converting a downlink signal transmitted from a base station into a baseband signal; A downlink control signal analyzer detecting downlink control information from the downlink baseband signal and detecting uplink subchannel allocation information included in the downlink control information; An uplink signal converter for converting an uplink signal transmitted from a terminal into a baseband signal; A service subchannel detector for separating uplink subchannels from the uplink baseband signal based on the uplink subchannel allocation information and detecting a subchannel relayed by the repeater among the subchannels; And a call counter that counts the number of the service subchannels as the number of calls being relayed by the repeater. The method of claim 1, wherein the downlink control signal analyzer, An FFT unit for converting the downlink baseband signal into a frequency domain signal by performing a fast fourier transform (FFT); A downlink FCH / UL-MAP detection / demodulator for detecting downlink frame control header (FCH) and uplink map (UL-MAP) regions from the downlink frequency domain signal and demodulating FCH information and UL-MAP information; And an uplink subchannel allocation information detector for detecting the uplink subchannel allocation information from the FCH information and the UL-MAP information. The method of claim 1, wherein the service subchannel detector, An FFT unit for converting the uplink baseband signal into a frequency domain signal by performing a fast fourier transform (FFT); An uplink subchannel separator for separating the uplink subchannels from the uplink frequency domain signal based on the uplink subchannel allocation information; A subchannel energy detector for detecting energy of each of the subchannels; And a comparator for comparing the energy of each of the subchannels with a preset threshold to detect a subchannel having energy above the threshold as the service subchannel. The relay service of claim 3, wherein the threshold is set to a range of energy values that an uplink signal corresponding to a subchannel allocated to a terminal within a relay service range of the repeater among the subchannels may have. Arc counting device.

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