KR20000059130A - Apparatus of advanced beacon possible to hard hand off - Google Patents

Abstract

PURPOSE: A beacon device capable of performing a hard handoff is provided to generate an optimum beacon signal which does not interfere in a neighboring channel by minimizing a system delay, and to maintain spectrum characteristics by excellent spurious characteristics. CONSTITUTION: A beacon device capable of performing a hard handoff comprises a mixer(100), a surface acoustic wave filter(110), an amplifier(120), an automatic gain controller(130), a quadrature phase shift keying(QPSK) demodulator(140), a separator(150), a pilot searcher(160), a pilot in-phase/quadrature(I,Q) generator(170), a delayer(180), and a QPSK modulator(190). The mixer mixes 18,19,20 frequency allocation(FA) signals with a local signal(L). The surface acoustic wave filter receives an intermediate frequency(IF) signal from the mixer to delay a system or improve a cut off capacity. The amplifier amplifies the IF signal to transmit the signal to the automatic gain controller. The automatic gain controller controls a gain of the IF signal to change the signal into a linearized signal. The QPSK demodulator receives the local signal to transmit an output signal to the separator. The pilot searcher obtains an initial synchronous signal to transmit the signal to the pilot I/Q generator. The pilot I/Q generator receives generates I/Q signals to output the signals to the delayer. The delayer delays the I/the Q signals for a regular time to transmit the signals to an output terminal(OUT).

Description

Apparatus of advanced beacon possible to hard hand off}

The present invention relates to an improved beacon device capable of hard handoff, and more particularly, hard handoff by performing 3 FA (Frequency Allocation) optical relaying using a pilot searcher. It relates to an improved beacon device that enables a stable service.

Code Division Multiple Access (CDMA) mobile phone signals are converted to optical signals in order to expand the coverage area of mobile phone base stations within a specific area, and they are transmitted from the main hub to the outskirts in a single optical fiber and transmitted from the outskirts. The optical signal is restored to a CDMA signal for each operator to serve a personal mobile station. At this time, the state monitoring and control of a plurality of remote locations to the NMS (Network Management System) through the frequency shift keying (FSK) modem and adopts a modular assembly. In addition, the optical transmission part implements bidirectional communication by a single core.

International Standard (IS) -95 based handoff service includes soft handoff and hard handoff. Soft handoff provides simultaneous communication between two base stations while the mobile station is in service between the serving base station and an adjacent base station. The hard handoff method refers to a call allocated to each other, and when a frequency used by a base station in service and a neighboring base station is different from each other, the call is disconnected from the current frequency and replaced by a new frequency supported by the neighboring base station.

In the general CDMA system, the difference in the number of FAs used between the base stations even in the downtown and the outskirts or the same downtown area due to the increase in the number of FAs due to the increase of subscribers is shown. In order to induce a smooth handoff between the cell C1, the outer small FA base station cell C2, and the downtown small FA base station cell C3, a pilot beacon method, which is a frequency method providing only a pilot channel without a traffic channel, is used. The IS-95-based hard handoff method is a method in which the mobile station transitions and the traffic channel is temporarily disconnected when the framed active offset is changed in the disconnected active set or the same CDMA FA. .

A beacon device for an optical repeater using a CDMA hard handoff scheme moves mobile stations between base stations separated by different FAs, and the base station transmits a handoff indication message to instruct CDMA to CDMA hard handoff. At the active time specified in the indication message, the mobile station disables its transmitter. The mobile station also performs pilot acquisition in the new active set and tunes the assigned Forward Traffic Channel.

However, a beacon device for an optical repeater using such a general CDMA hard handoff method has the following problems.

Since the beacon is a signal transmitted through the optical repeater, the spurious characteristic of the signal itself is reduced, and since the system delay time through the optical repeater is long, adding the filtering delay of the surface acoustic wave filter after down-conversion causes a delay of more than a predetermined time, so that the adjacent FA Interference causes performance degradation, and even when surface acoustic wave filters are used, it is difficult to maintain spurious characteristics, thereby retaining malformed spectral characteristics.

Accordingly, an object of the present invention is to solve such a problem, and an object of the present invention is to down-convert a FA transmitted from an optical repeater and to obtain a high quality beacon signal after synchronizing with a pilot searcher to generate a high quality beacon signal. The present invention provides an improved beacon device capable of minimizing hard handoff without interfering with adjacent channels.

Another object of the present invention is to down-convert a predetermined number of FAs to 19 FA center frequencies, and then use a predetermined frequency band as a beacon, thereby maintaining a system delay at all times, thereby improving hard handoff with improved spurious characteristics. To provide a beacon device.

1 illustrates a typical CDMA base station cell range,

2 is a block diagram of an improved beacon device capable of hard handoff according to the present invention.

<Explanation of symbols for main parts of drawing>

100: blender 110: surface acoustic wave filter

120: amplifier 130: automatic gain controller

140: QPSK demodulator 150: separator

160: pilot search 170: pilot I, Q generator

180: delay 190: QPSK modulator

In order to achieve the above object, a feature of the present invention is a beacon apparatus capable of hard handoff, comprising: a mixer for mixing a predetermined number of FA signals and local signals transmitted through an input terminal; A surface acoustic wave filter for receiving a signal output from the mixer to improve system delay and cutoff performance; An amplifier for amplifying the signal output from the surface acoustic wave filter; An automatic gain controller which controls the gain of the signal amplified by the amplifier and changes it into a linearized signal; A QPSK demodulator for inputting a local signal to demodulate the linearized signal output from the automatic gain controller; A separator for separating the I and Q signals of the predetermined band signal demodulated by the QPSK demodulator; A pilot searcher for inputting I and Q signals separated by the separator to obtain initial synchronization; A pilot I and Q generator receiving pilot signals output from the pilot searcher and generating pilot I and Q signals; A delay unit for delaying the I and Q signals output from the pilot I and Q generators for a predetermined time; And a QPSK modulator that receives the I and Q signals output from the delayer, modulates them, and sends them to an output terminal.

Meanwhile, the FA signal input to the mixer is characterized in that the 18, 19, 20 FA signal.

Meanwhile, the signal filtered by the surface acoustic wave filter is an intermediate frequency signal.

On the other hand, the I, Q signal separated in the separator is characterized in that the signal having a bandwidth of 630KHz.

On the other hand, the pilot searcher is composed of a cross correlator and a digital match filter, characterized in that to obtain an initial synchronization signal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an improved beacon device capable of hard handoff according to the present invention.

2, the present invention includes a mixer 100, a surface acoustic wave filter 110, an amplifier 120, an automatic gain controller 130, a QPSK demodulator 140, a separator 150, and a pilot. The searcher 160, the pilot I, the Q generator 170, the delay unit 180, and the QPSK modulator 190 is composed of.

In detail, the mixer 100 mixes the 18, 19, and 20 FA signals and the local signal L transmitted through the input terminal IN, and the surface acoustic wave filter 110 is an intermediate output from the mixer 100. Receive frequency signals to improve system delay and cutoff performance. At this time, the system delay time is 10.5 μsec by adding 7 μsec of the optical repeater (not shown) and 3.5 μsec of the surface acoustic wave filter 110.

The amplifier 120 amplifies the intermediate frequency signal filtered by the surface acoustic wave filter 110 and transmits the amplified intermediate frequency signal to the automatic gain controller 130. The automatic gain controller 130 controls the gain of the intermediate frequency signal amplified by the amplifier 120 and changes it into a linearized signal. At this time, the intermediate frequency signal output from the automatic gain controller 130 is input to the QPSK demodulator 140, the QPSK demodulator 140 receives the local signal (L) and transmits the output signal to the separator 150.

Since the intermediate frequency signal output from the QPSK demodulator 140 has a spurious of about 32 to 34 dB of 750 KHz, and cannot pass the spurious specification, the separator 150 is separated into an I and Q signal having a bandwidth of 630 KHz and is pilot-searched. It is input to 160.

The pilot searcher 160 is composed of a cross correlator (not shown) and a digital match filter (not shown) to obtain an initial synchronization signal and send it to the pilot I and Q generators 170. The pilot I and Q generators 170 receive the synchronization signal output from the pilot searcher 160, generate pilot I and Q signals, and output the pilot I and Q signals to the delay unit 180.

The delay unit 190 delays the pilot I and Q signals for a predetermined time and sends them to the output terminal OUT through the QPSK modulator 190 which modulates the pilot I and Q signals. Modulated pilot I and Q signals output through the output (OUT) can automatically configure the PN offset without the need to input the network or PN offset using RS-232.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As a result, according to the improved beacon device capable of hard handoff according to the present invention, the following advantages occur.

In other words, the system delay is minimized to generate an optimal beacon signal that does not interfere with the adjacent channel, and has excellent spurious characteristics, thus maintaining the formal spectral characteristics.

Claims (5)

A beacon device capable of hard handoff, A mixer for mixing a predetermined number of FA signals and local signals transmitted through an input terminal; A surface acoustic wave filter for receiving a signal output from the mixer to improve system delay and cutoff performance; An amplifier for amplifying the signal output from the surface acoustic wave filter; An automatic gain controller which controls the gain of the signal amplified by the amplifier and changes it into a linearized signal; A QPSK demodulator for inputting a local signal to demodulate the linearized signal output from the automatic gain controller; A separator for separating the I and Q signals of the predetermined band signal demodulated by the QPSK demodulator; A pilot searcher for inputting I and Q signals separated by the separator to obtain initial synchronization; A pilot I and Q generator receiving pilot signals output from the pilot searcher and generating pilot I and Q signals; A delay unit for delaying the I and Q signals output from the pilot I and Q generators for a predetermined time; And And a QPSK modulator for receiving the I and Q signals output from the delay unit and modulating the I and Q signals to an output terminal. The method of claim 1, Improved beacon device capable of hard hand off, characterized in that the FA signal input to the mixer is 18, 19, 20 FA signal. The method of claim 1, And a signal filtered by the surface acoustic wave filter is an intermediate frequency signal. The method of claim 1, Improved beacon device capable of hard hand off, characterized in that the I, Q signal separated in the separator is a signal having a bandwidth of 630KHz. The method of claim 1, wherein the pilot searcher An improved beacon device capable of hard handoff, comprising a cross correlator and a digital match filter to obtain an initial sync signal.