KR20010009621A - Modulation/demodulation apparatus capable of hand-off and the method for hand-off in two different cdma mobile communication system - Google Patents

Abstract

PURPOSE: A modulating/demodulating device capable of performing handoff in two different CDMA(Code Division Multiple Access) mobile communication systems is provided to support all modulating methods according to an IS-95A/B standard and an IS-95C standard in a transmitter, to synthesize all data in accordance with the two standards to output the synthesized data, and to receive all data received from a base station according to the IS-95A/B standard and from a base station according to the IS-95C standard in a receiver. CONSTITUTION: The first modulator(103) modulates channel-coded data to transmit the modulated data, according to a modulating method of the first base station. The second modulator(105) modulates the channel-coded data to transmit the modulated data, according to a modulating method of the second base station. A controller(159) operates one of the first modulator(103) and the second modulator(105) when the two base stations independently perform communication, and operates the first modulator(103) and the second modulator(105) when handoffs are carried out between the two base stations, to transmit data.

Description

{MODULATION / DEMODULATION APPARATUS CAPABLE OF HAND-OFF AND THE METHOD FOR HAND-OFF IN TWO DIFFERENT CDMA MOBILE COMMUNICATION SYSTEM}

The present invention relates to a demodulation device and a handoff method of a code division multiple access mobile communication system, and more particularly, to a demodulation device and a handoff method capable of handoff in two different systems.

In general, a code demodulation multiple access (CDMA) mobile demodulator uses a modulator and a demodulator, and its configuration is configured to satisfy a standard such as IS-95. Currently, the IS-95 standard is divided into IS-95A, IS-95B, and IS-95C. The IS-95A and IS-95B standards are almost similar and compatible with the same configuration. That is, IS-95A and IS-95B use BPSK in the forward direction, and the same modulation and demodulation scheme in the reverse direction, that is, IS-95A and B use 64-ary modulation. However, the IS-95C uses QPSK in the forward direction and 4-8 Walsh codes in the reverse direction, unlike the IS-95A and IS-95B modulation and demodulation schemes. (Hereinafter, IS-95A and IS-95B using the same modulation and demodulation method are referred to as "IS-95A / B").

In this case, it is not a problem when the IS-95A / B and IS-95C mobile communication systems communicate with each other, but handoff from IS-95A / B to IS-95C or from IS-95C to IS-95A / B. If the two systems do not provide compatibility, handoff cannot be performed and communication cannot be performed. In order to solve this problem, it is necessary to have a demodulation device that satisfies IS-95A / B and IS-95C at the same time. In order to satisfy IS-95A / B and IS-95C at the same time, the demodulator of the terminal must support BPSK and QPSK types, and the modulator must be used for both IS-95C and IS-95A / B.

Accordingly, an object of the present invention is to provide a demodulation device and a handoff method having compatibility capable of performing communication by performing handoff between two different code division multiple access mobile communication systems.

An object of the present invention is to provide a demodulation device and a handoff method capable of simultaneously performing BPSK and QPSK modulation and demodulation in a forward direction of two different code division multiple access mobile communication system demodulation devices.

Another object of the present invention is to provide a demodulation device and a handoff method capable of simultaneously performing 64-ary modulation and a demodulation by Walsh code in a reverse direction of two different code division multiple access mobile communication system demodulation devices.

In order to achieve the above object, the present invention provides a mobile communication system including first and second base stations operating in different modulation and demodulation methods, wherein the data is channel coded according to the modulation method of the first base station under predetermined control. A first modulator for modulating and transmitting the first modulator, a second modulator for modulating and transmitting the channel coded data according to a modulation method of the second base station under predetermined control, and the second modulator independently performing communication at each base station. And a controller for operating one of the first modulator or the second modulator, and for transmitting data by operating the first and second modulators during handoff between the first and second base stations.

In order to achieve the above object, the present invention provides a mobile communication system having first and second base stations operating in different modulation and demodulation schemes, and outputs base station information and channel state information by receiving a pilot signal through a pilot channel. A searcher, a controller which receives the base station information and the channel state information and outputs channel allocation information and a control signal, assigns a finger to the first and second base stations by the channel allocation information and the control signal, A finger processor for collecting and outputting data output from a plurality of fingers assigned to each other; a combiner for receiving the control signal and combining and outputting data collected for each base station; and receiving the control signal. Channel decoder to decode and output the data output from the combiner. And a gong.

In order to achieve the above another object, the present invention provides a handoff method between base stations operating in different modulation and demodulation schemes in a mobile communication system, wherein a handoff direct message received from a first base station currently communicating at the time of handoff is examined. Determining whether a second base station which is a base station to be handed off uses a modulation and demodulation scheme different from that of the first base station, and assigning a finger to a second base station if the second base station uses a modulation and demodulation scheme different from that of the first base station, Enabling the combiner and channel decoder and modulator for the second base station, communicating with the two base stations simultaneously until a handoff complete message is received from the first base station, and the handoff Upon receiving the completion message, the finger for the first base station is released, and the combine for the first base station is performed. And it characterized by constituted by any process for disabling the operation of the channel decoder and modulator.

1 is a block diagram of a modulation device according to an embodiment of the present invention.

2 is a block diagram of a demodulation device according to one embodiment of the present invention;

FIG. 3 is a diagram showing the configuration of the finger unit and the finger output control unit of FIG. 2; FIG.

4 is a detailed block diagram of the finger of FIG. 3;

Fig. 5 is a detailed block diagram of the combiner portion of Fig. 2;

6 is a flowchart illustrating a handoff method in a demodulation device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the present invention, in order for all terminals in the IS-95A / B network and the IS-95C network to communicate with each other, the base station must transmit both an IS-95A / B modulation signal and an IS-95C modulation signal. . To this end, the present invention is configured as shown in FIG. 1 and will be described in detail with reference to FIG. 1.

The encoder 101 receives predetermined data and performs channel coding, that is, encoding and interleaving, and outputs data symbols. The data symbols are input to the first modulator 103 and the second modulator 105. The first modulator 103 is a modulator according to the IS-95A / B standard, and the second modulator 105 is a modulator according to the IS-95C standard. The first modulator 103 outputs the data symbol by performing binary phase shift modulation (BPSK). The second modulator 105 performs output by performing QPSK modulation. The first modulator 103 and the second modulator 105 operate by receiving control information from the controller 113. In the IS-95A / B network, the first modulator 103 is operated, and in the IS-95C network, the second modulator 105 is operated. When handing off from IS-95A / B to IS-95C network or when handing off from IS-95C to IS-95A / B, the first modulator 103 and the second modulator 105 are performed until the handoff is completed. ) All work. The first modulator 103 receives first control information, and the second modulator 105 receives second information to operate. The controller 113 receives handoff information from a base station through a receiving end and outputs first control information to the first modulator 103 and second information to the second modulator 105. The data symbols modulated by the first modulator 103 are input to the first power amplifier 107, and the data symbols modulated by the second modulator 105 are input to the second power amplifier 109. The first power amplifier 107 receives a predetermined first power control signal and controls and outputs power of the data symbol, and the second power amplifier 109 receives a predetermined second power control signal to receive the data symbol. Control the power of the output. The first and second power control signals are output from a demodulator of a receiver to be described later. The data symbols output from the first power amplifier 107 and the data symbols output from the second power amplifier 109 are input to the adder 111. The adder 111 receives only the data symbols output from the first power amplifier 107 in the IS-95A / B network and outputs them to the RF unit 115, and the second power amplifier 109 in the IS-95C network. Receives only the data symbols output from the) and outputs to the RF unit 115. However, when handing off from IS-95A / B to IS-95C or when handing off from IS-95C to IS-95A / B, the first power control amplifier 107 and the second power control amplifier 109 are output. Both data symbols are input, the two data symbols are added, and output to the RF unit 115. The RF unit 115 loads the data symbols output from the adder 111 on a carrier and transmits them through an antenna.

As described in FIG. 1, the terminal according to the present invention simultaneously accesses the two different networks when handing off from the IS-95A / B network to the IS-95C network or from the IS-95C network to the IS-95A / B network. To do this, the same data is modulated and transmitted in two modulation schemes so that the base stations of the two networks can receive the data. At this time, the two base stations each receive only corresponding data. This is because the two data have identifiers for distinguishing corresponding base stations, and modulation methods are different.

2 is a block diagram illustrating a demodulation device according to an embodiment of the present invention. Hereinafter, a receiver configuration and operation of a terminal for simultaneously receiving data from the two networks when handing off different networks IS-95A / B and IS-95C will be described with reference to FIG. 2.

The searcher 156 detects the base station capable of handoff and communication by detecting the strength of the pilot signal received from the adjacent base stations through the pilot channel periodically under the predetermined control, and detects information about the base station and the channel environment state. Output channel information. The controller 159 receives base station information and channel environment information from the searcher 156 and outputs an enable signal and finger allocation information.

Finger portion 120 is composed of a plurality of fingers (121 ~ 127) as shown in Figure 3 receives the enable signal from the controller 159, respectively, according to the enable signal IS-95A / B and IS- Operates at one of 95Cs.

FIG. 4 is a detailed configuration diagram of each finger of FIG. 3 and will be described in detail with reference to FIG. 4.

First, the PN generator 215 generates a PN code. The despreader 201 receives in-phase data (“I”) and quadrature-phase (“Q”) data and receives the PN generator 215. ) Receives PN code outputted from) and despreads it. The time tracker 216 receives the I and Q data for timing recovery, performs timing tracking, outputs an error estimation signal to the PN generator 215, and provides a tracked timing clock to the lock state detector 217. do. The lock state detector 217 receives the I and Q data, determines whether the I and Q data are locked, and outputs the lock state information to the delay compensator 213. The lock state information is information for determining whether the currently received data is useful.

The frequency error compensator 205 receives the I and Q data, estimates the frequency error, and outputs frequency error estimation information. The Walsh reconstructor 203 receives a first enable signal and operates when the first enable signal is “1” (or “0”). The Walsh reconstructor 203 receives I data and 64-ary codes among the I and Q data despread by the despreader 201 and performs Walsh reconstruction according to IS-95A / B. The frequency error estimation information output from 205 is input and compensated for, thereby outputting the frequency error. Data extracted from the Walsh restorer 203 is input to the A terminal of the mux 211.

The second Walsh reconstructor 207 operates by receiving a first enable signal and operates when the first enable signal is “0” (or “1”). The second Walsh reconstructor 207 receives I and Q data and a 128-ary Walsh code from the despreader 201 and performs Walsh reconstruction according to IS-95C, and outputs the frequency error compensator 205. The frequency error estimation information is input to compensate for the frequency error, and outputs I and Q data. The I and Q data output from the second Walsh reconstructor 207 are converted into serial data by the parallel / serial converter 209 and input to the B terminal of the mux 211.

The MUX 211 receives the first enable signal and selects and outputs the A or B terminal. That is, when the first enable signal is "1", Walsh-restored data is output to the delay compensator 213 according to IS-95A / B input to the A terminal. When the first enable signal is "0", The Walsh restored data is output to the delay compensator 213 according to IS-95C inputted to the B terminal.

The delay compensator 213 delays the symbol lock state information for the delay time to synchronize the symbol lock state information output from the lock state detector 217 with data having a predetermined delay time than the symbol lock state information. The data is output to the combiner 140 together with the data about the symbol lock state information.

The received data output from the finger unit 120 is input to the finger output control unit 130. The input finger output controller 130 collects the data output from the finger assigned to the same base station, that is, the IS-95A / B base station, and the data output from the finger assigned to the base station in the IS-95C. 3 collects and outputs output data of a finger assigned to IS-95A / B through a first output port, and outputs output data of a finger assigned to IS-95C through a second output port. The finger output controller 130 has 1 × 2 demux as many as the number of fingers therein. The demux includes a first output port and a second output port as output ports, and selects an output port by receiving 1 bit of finger assignment information. Accordingly, n bits are input in the finger allocation information equal to the number of fingers. The finger output controller 130 uses one of the first output port and the second output port when communicating in an independent network, and when the terminal uses both the first output port and the second output port, the terminals output each other. It is used to perform soft handoff when performing handoff in other IS-95A / B and IS-95C networks.

The combiner 140 includes a first combiner 160 and a second combiner that receive data output from the first and second output ports of the finger output controller 130, respectively, as shown in FIG. 161, and is enabled / disabled under the control of the controller 159. The combiners 160 and 161 receive data output from the first output port and the second output port of the finger output controller 130, respectively, and combine the power control bits in a chip unit to provide power control information. The data in the chip unit is combined and output in the symbol unit. When the enable signal is performing communication in an independent network, only one of the first combiner 160 or the second combiner 161 is used, and the two combiners 160 in different standardization networks are used. 161 are all enabled.

In FIG. 5, the first and second combiners 160 and 161 include power control bit combiners 145 and 148 and symbol combiners 146 and 147, respectively. The power control bit combiners 145 and 148 combine power control bits received through a pilot channel under the control of the controller 159 to output power control information, and the symbol combiners 146 and 147. ) Combines the data in symbol units and outputs them.

The first channel decoder 151 is a K = 9 and R = 1/3 decoder, and decodes and outputs data symbols output from the first combiner 160. The second channel decoder 153 is a K = 9 and R = 1/4 decoder, and decodes and outputs a data symbol output from the second combiner 161.

As described above, the receiver of the present invention supports communication in both the IS-95A / B network and the IS-95C network, and is supported by the IS-95A / B to perform soft handoff during handoff between the two networks. Part and all parts supported by the IS-95C.

6 is a flowchart illustrating a handoff method in a demodulation device according to an embodiment of the present invention. Hereinafter, FIG. 6 will be described with reference to the configuration of FIGS. 1 to 5.

In the handoff according to the present invention, there is a case of handoff from an IS-95A / B network to an IS-95C network, and a case of handoff from an IS-95C network to an IS-95A / B network. First, when handing off from an IS-95A / B network to an IS-95C network and a handoff from an IS-95C network to an IS-95A / B network, the same procedure is performed except that the description is different. Note that only the case of handoff from the IS-95C network to the IS-95A / B network will be described.

First, the controller 159 of the terminal searches for the base station by detecting the PN offset information received through the pilot channel in step 601 through the searcher 156. When the PN offset information is detected from the predetermined base station, the controller 159 detects the signal strength of the PN offset information in step 603 and checks whether it exceeds a predetermined value. If the signal strength of the detected PN offset information exceeds a predetermined value, the controller 113 generates a pilot strength measurement message (PSMM) to the IS-95C base station and transmits it to the base station in step 605. The predetermined value is T_ADD, which is a value defined in IS-95. After transmitting the PSMM message to the base station, the controller 159 checks whether a handoff direction message (HDM) is received from the base station in step 607. The HDM message includes information about neighboring base stations, for example, whether the neighboring base station supports IS-95A / B or IS-95C, a system identification (SID), and a SAT color code (SCC). , A message having information such as a message encryption mode indicator (MEM). In this case, when the HDM message is received from the base station, the controller 159 analyzes the HDM message in step 609 and determines whether the information is information about the IS-95A / B base station or about the IS-95C base station. If the HDM message is information about the IS-95A / B base station, the controller 159 proceeds to step 611. If the HDM message is a base station supporting the same IS-95C as the currently communicating base station, the controller performs a general handoff process. However, in step 611, the controller 159 outputs "1" as the first enable signal to some of the plurality of fingers constituting the finger 120 and allocates the IS-95A / B for use. At this time, the rest is operated as a finger for the IS-95C. When the IS-95A / B finger is assigned, the controller 159 outputs and operates the second enable signal of the first combiner 160 and the first channel decoder 151 in step 613. Therefore, when a handoff occurs between the IS-95A / B and the IS-95C, both the first combiner 160 and the second combiner 161, the first channel decoder 151, and the second channel decoder 153 operate. Done. After step 613, the controller 159 proceeds to step 615 to enable and activate the first modulator. Before step 615, the transmitting end operates only the second modulator 105, but after step 615, the first modulator 103 also operates. Therefore, the transmitter adds and transmits the data according to the IS-95A / B standard and the data according to the IS-95C standard. In this case, a preset initial value is input to the first power control signal and the second power control signal. If both the first modulator 103 and the second modulator 105 are enabled in step 615, the controller 159 checks whether data is received from the IS-95A / B base station in step 617. When the data is received in step 617, the controller 159 transmits the first power control bit combiner 145 and the first power control bit received through the finger assigned to the corresponding pilot channel among the data in step 619. 2 is output to the power control combiner 148 and combined. The controller 159 generates a first power control signal and a second power control signal using the combined power control bits in step 621. The controller 159 outputs the generated first power control signal to the first power control amplifier 107 in step 623 and outputs the second power control signal to the second power control amplifier 109 to perform power control. do. During the process, the controller 159 checks whether a handoff completion message is received from the IS-95C base station in step 625. In this case, when the handoff completion message is received, the controller 159 disables the finger, combiner, and channel decoder allocated for the IS-95C in operation 627, and then operates only the IS-95A / B support mode.

As described above, the present invention supports both modulation schemes according to IS-95A / B and IS-95C standards in a transmitter, synthesizes and outputs data according to the two standards during handoff, and IS-95C in a receiver. Since all data received from the base station according to the standard and the base station according to the IS-95A / B standard can be received, there is an advantage of providing compatibility between the IS-95A / B and the IS-95C.

Claims (19)

A mobile communication system comprising first and second base stations operating in different modulation and demodulation schemes, A first modulator for modulating and transmitting channel coded data according to a modulation method of the first base station under predetermined control; A second modulator for modulating and transmitting the channel coded data according to a modulation method of the second base station under predetermined control; The controller is one of the first modulator or the second modulator when the base station independently performs communication, and the controller transmits data by operating the first and second modulators during handoff between the first and second base stations. In the code division multiple access mobile communication system characterized in that the handoff available in two different systems. The code division multiple access mobile communication system of claim 1, further comprising a first power control amplifier for controlling and outputting power of data output from the first modulator according to a predetermined control signal. Handoffable modulation device in two systems. The code division multiple access mobile communication system of claim 1, further comprising a second power control amplifier for controlling and outputting power of data output from the second modulator according to a predetermined control signal. Modulator capable of handoff in two systems. And an adder for adding and outputting data output from the first modulator and the second modulator during the handoff. 2. The modulation and demodulation device as claimed in claim 1, wherein the first modulator is a binary phase modulator. 2. The modulation and demodulation device as claimed in claim 1, wherein the second modulator is a quadrature phase modulator. A mobile communication system comprising first and second base stations operating in different modulation and demodulation schemes, A searcher for receiving a pilot signal through a pilot channel and outputting base station information and channel state information; A controller for receiving the base station information and the channel state information and outputting channel allocation information and a control signal; A finger processor for allocating a finger to the first and second base stations according to the channel assignment information and a control signal, and collecting and outputting data output from a plurality of fingers respectively assigned to the corresponding base station; A combiner for receiving the control signal and combining and outputting data collected for each base station; And a channel decoder configured to receive the control signal and decode the data output from the combiner, respectively, and output the decoded channel decoder. 2. The method of claim 7, wherein the finger processing unit, Finger part consisting of a plurality of fingers, Two different systems in a code division multiple access mobile communication system comprising a finger output control unit for receiving the finger assignment information and collecting and outputting data output from a finger assigned to each of the first and second base stations for each base station Demodulator capable of handoff from The demodulation device as claimed in claim 8, wherein the finger assignment information is input in the same number of bits as the number of the fingers. The method of claim 9, wherein each of the fingers, A despreader that receives predetermined in-phase data and quadrature data and despreads them and outputs them; A first Walsh restorer which operates by receiving the control signal, receives a first Walsh code, and restores and outputs the in-phase data by Walsh; A second Walsh restoration unit configured to receive the control signal and operate and receive a second Walsh code and restore and output the in-phase data and quadrature-phase data by Walsh; In the code division multiple access mobile communication system, a handoff can be demodulated by two different systems in the code division multiple access mobile communication system, wherein the selector receives the control signal and selects and outputs data output from the first Walsh restorer and the second Walsh restorer. Device. The demodulation device as claimed in claim 10, wherein the first Walsh code is a 64 array Walsh code. 12. The demodulation device as claimed in claim 11, wherein the second Walsh code is a 128 array Walsh code. The method of claim 12, wherein the second Walsh restoration unit, A second Walsh restorer that receives the first Walsh code and restores and outputs the in-phase data and quadrature data by Walsh; Hand-off demodulation in two different systems in a code division multiple access mobile communication system comprising a parallel / serial converter for serially converting in-phase data and quadrature data output from the second Walsh reconstructor Device. The method of claim 13, wherein the combiner, A power control bit combiner for detecting and combining the power control bits from the data output from the finger processor; And a symbol combiner for detecting and combining data symbols from the data output from the finger processor. The method of claim 7, wherein the channel decoder, A first channel decoder for channel decoding the received data symbols received from the first base station and combined; And a second channel decoder for channel decoding the data symbols received and received from the second base station, wherein the demodulator can be handed off in a multiplexing mobile communication system. 16. The demodulation device as claimed in claim 15, wherein the first channel decoder is a decoder for an encoder having a constraint length of 9 and a code rate of 1/3. 17. The demodulation apparatus as claimed in claim 16, wherein the second channel decoder is a decoder for an encoder having a constraint length of 9 and a code rate of 1/4. In a handoff method between base stations operating in different modulation and demodulation schemes in a mobile communication system, Inspecting a handoff direct message received from a first base station currently in communication during handoff to determine whether a second base station, which is a base station to be handed off, uses a different modulation and demodulation scheme than the first base station; If the second base station uses a modulation and demodulation scheme different from that of the first base station, allocating a finger for the second base station, enabling a combiner, a channel decoder, and a modulator for the second base station; Communicating with the two base stations simultaneously until a handoff complete message is received from the first base station; And releasing a finger for the first base station and disabling operations of a combiner, a channel decoder, and a modulator for the first base station when the handoff complete message is received. The method of claim 18, wherein the determination process, Searching for a base station newly registered in the pilot strength strength message; If there is a newly registered base station, transmitting the pilot strength strength message to the first base station; When a handoff direct message is received in response to the pilot strength strength message, it is determined whether the information in the handoff direct message is information about a second base station, and the second base station is a base station using a modulation and demodulation scheme different from that of the first base station. Determining the method comprising the steps of: