KR100264828B1 - Interface method of pcm data for a vocoder - Google Patents

Abstract

PURPOSE: A PCM(Pulse Code Modulation) data interface method of a vocoder is provided to set up a DS0 channel-to-a vocoder channel as 1:N. CONSTITUTION: A CPU(10) sets a channel value of a DS0 assigned to each vocoder(20) to a channel register of an inner PCM(Pulse Code Modulation) interface(30), and transmits bit offsets and bit sizes to the each vocoder(20). When PCM data is transmitted to the each vocoder(20) from an exchange station, the each vocoder(20) processes corresponding bits as much as the bit sizes from bits separated as much as the bit offsets. When the each vocoder(20) transmits the PCM data to the exchange station, the each vocoder(20) loads the bits as much as the bit size on a corresponding DS0 PCM channel, and transmits the PCM channel to the exchange station.

Description

Vocoder PCM Data Interface Method

The present invention relates to a PCM data interface for data communication in a CDMA mobile communication system. In particular, the VOCODER between a control station and an exchange station implements a PCM data interface in units of 8 bits or less to provide multiple subscribers in one PCM channel. The present invention relates to a PCM data interface method of a VOCODER for servicing data on a VOCODER.

In the above description, VOCODER is an abbreviation of Voice Coder and is a kind of apparatus for band compression of voice. Paying attention to the fact that the audio signal is regarded as the output of the resonance system excited according to the sound source, the audio signal is decomposed into several parameters representing the characteristics of the sound source and the resonance system, and the receiving side synthesizes the original audio signal according to these parameters. It is. Types of vocoder include channel vocoder, formant vocoder, linear predictive vocoder, PARCOR vocoder, etc., and the voice can be compressed and transmitted from one to tens of minutes.

PCM data transmission and reception apparatus of a general CDMA mobile communication system applying the vocoder as described above is shown in FIG.

As shown therein, the modem 1 for transmitting and receiving voice with the terminal and the user voice obtained from the modem 1 are compressed by band compression and transmitted to the switching center, and the PCM data transmitted from the switching station is demodulated. It consists of a vocoder (2) for transmitting to the modem (1), and a PCM interface unit (3) for interfacing the PCM data between the vocoder (2) and the switching center.

In the PCM data transmission / reception apparatus of the general CDMA mobile communication system configured as described above, the interface between the vocoder 2 and the PCM of the control station is implemented such that one vocoder channel corresponds to 1 PCM channel (8 bits) 1: 1.

The narrowband CDMA system transmits and receives data at 8kbps in the AIR section, while the DS0 interface (PCM channel) between the vocoder 2 and the switching center supports 64Kbps. In the case of data communication or communication between terminal users, the vocoder 2 operates in bypass mode, that is, data is passed without encoding / decoding. In this case, the compressed data is transmitted and received at 8Kbps through the DS0 interface, so the vocoder channel and the PCM channel are used. If 1: 1 is assigned, the PCM channel is idle.

2 is a detailed configuration diagram of a PCM data interface device of a conventional control station vocoder.

As shown here, the central processing unit 4 which controls the transmission and reception, encoding and decoding of the PCM data, the vocoder 5 for band compression or decompression of the voice data, and the PCM data between the vocoder 5 and the switching center It consists of a PCM interface unit 6 for interfacing.

In the PCM data interface procedure of the conventional control station vocoder configured as described above, when PCM data such as (d) of FIG. 3 is transmitted from the switching center, the PCM interface unit 6 gives the vocoder 5 an 8-bit starting point of the PCM channel. The SYNCINn signal is transmitted as shown in FIG. 3B, and at the same time, the clock CLKIN as shown in FIG. Then, the vocoder 5 synchronizes with the clock CLKIN, takes 8-bit PCM data from the corresponding channel, processes it, and passes it to the central processing unit 4.

Next, referring to the process of transmitting PCM data from the vocoder 5 to the switching center, the vocoder 5 sends a signal to the PCM interface unit 6 as shown in FIG. 3 (f) indicating the 8-bit starting point of the PCM channel. As a result, the PCM interface unit 6 transmits a clock CLKOUT as shown in FIG. 3E to the vocoder 5. Then, the vocoder 5 carries 8-bit PCM data such as (h) and (i) of FIG. 3 on the corresponding PCM channel in synchronization with the data output clock CLKOUT.

That is, the vocoder is fixed to access its PCM channel fixed in hardware on DS0 (64Kbps / CH) in 8-bit units, so that the vocoder channel transmitted / received through DS0 is also assigned to the DS0 channel 1: 1. It is.

Therefore, in the conventional CDMA mobile communication system as described above, when the data communication using the vocoder bypass mode, the vocoder channel corresponds to 8 bits: 8 bits to the PCM channel, so that the 8Kbps data from the terminal is 64Kbps PCM channel. Because of this, the efficiency of the PCM channel is reduced.

Accordingly, the present invention has been proposed to solve the above problems of the conventional mobile communication system,

The present invention implements a PCM data interface in units of 8 bits or less in a VOCODER between a control station and an exchange station, so that the PCM of a VOCODER can serve data for multiple subscribers in one PCM channel. The purpose is to provide a data interface method.

Method according to the present invention for achieving the above object,

Setting a channel value of DS0 assigned to each vocoder in a channel register in the PCM interface unit when setting up a call of each vocoder channel, and transmitting a bit offset and a bit size to each vocoder;

When the PCM data is transferred from the switching center to the vocoder after the step, the respective vocoder processing the corresponding bit by the bit size from the bits spaced apart by the bit offset from the start signal of the PCM data;

In the case of transmitting PCM data from each vocoder to the switching center, each vocoder transmits the bit size of the bit to the corresponding PCM channel from the bits spaced apart by the bit offset from the PCM data transmission start signal. Characterized in that made.

1 is a schematic configuration diagram of a PCM data transmission / reception system of a general CDMA mobile communication system;

2 is a block diagram of a PCM data interface device of a vocoder in a conventional CDMA mobile communication system.

3 is a timing diagram of each sub-PCM data interface of FIG.

4 is a block diagram of a PCM data interface device of a vocoder in a CDMA mobile communication system according to the present invention;

5 is a timing diagram of each sub-PCM data interface of FIG. 4;

6 is a flowchart illustrating a PCM data interface method of a vocoder according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: central processing unit

20: Vocoder

30: PCM interface unit

4 is a block diagram of a PCM data interface device of a vocoder in the present invention.

As shown therein, the CPU 10 controls the transmission and reception of PCM data, sets the channel value of DS0 assigned to each vocoder in the channel register of the PCM interface unit, and provides a bit offset and a bit size to each vocoder. And a vocoder 20 for encoding and decoding PCM data by bit offset and bit size provided by the central processing unit 10, and a PCM interface unit for interfacing the PCM data between the vocoder 20 and the switching center. It consists of 30.

Referring to the PCM data interface method of the control station vocoder to which the present invention configured as described above is applied, the PCM data interface method according to the present invention will be described in detail with reference to FIGS. 5 and 6 as follows.

First, the CPU 10 receives a few bits (bit size) from the first bit (bit offset) of the PCM channel during call setup to the vocoder 20 through a bus connected to the vocoder 20. In addition, the channel register of the PCM interface unit 30 also sets the channel value of DS0 assigned to each vocoder.

In this state, the PCM interface unit 30 starts the signal SYNCINn of the DS0 PCM channel as shown in FIGS. 5B to 5E and the signal SYNCOUTn as shown in FIGS. 5H to 5J. Generates and delivers to the vocoder 20.

Accordingly, the vocoder 20 recognizes the start signal SYNCINn at the time of receiving PCM data (when receiving PCM data transmitted from the switching center), and transmits the data by the number of bits set from the bits separated by the bit offset from the channel start point. It reads from the PCM channel, processes it, and delivers it to the CPU 10.

In addition, the vocoder 20 recognizes the transmission start signal SYNCOUTn when PCM data is transmitted (when data obtained from the terminal is transmitted to the switching center), and sets the number of bits that are set by bits away from the channel start point by the bit offset. Data is transmitted on the PCM channel.

This enables 1: N between PCM channels and vocoder channels.

Hereinafter, the method in which four vocoders in the vocoder 20 process the data corresponding to the DS0 channel as four different vocoders with different bits will be described in more detail.

First, vocoder 0 is bit [5-4] of DS0 channel 0, vocoder 1 is bit [7-6] of DS0 channel 0, vocoder 2 is bit [3-0] of DS0 channel 0, and vocoder 3 is DS0 channel 1 If the call is set to be assigned to bit [7-0] of the vocoder 0, 1, 2 is the bypass mode for data communication, vocoder 3 is assumed to be assigned to the channel for voice communication, Figure 5 Regarding the timing, the PCM data interface process is as follows.

First, upon call setup of each vocoder channel, the central processing unit 10 sets the channel value of DS0 assigned to each vocoder in the channel register in the PCM interface unit 30, and bit offsets to each vocoder in the vocoder 20. And bit size.

In this state, when the PCM data is received, vocoder 0 in the vocoder 20 receives and processes bits of bit size, i.e., bits [5-4] of DS0 channel 0, from bits away from the SYNCIN0 signal by a bit offset, Similarly, the vocoders 1, 2, and 3 read and process bits allocated to each vocoder channel from the DS0 channel.

In addition, when transmitting PCM data, the vocoder 0 loads a bit size bit, that is, bits [5-4] of DS0 channel 0 to DS0 channel 0 from a bit offset from the SYNCOUT0 signal by a bit offset, and vocoder 1, 2, and 3 Likewise, the bits assigned to the channels assigned to each vocoder are carried on the DS0 channel.

In this way, three channels of vocoder for data communication are allocated to one channel of DS0 to efficiently use the PCM channel.

As described above, the present invention has an effect that the PCM channel can be efficiently used by setting the DS0 channel to the vocoder channel to 1: N when performing data communication in a narrowband CDMA system.

Claims (2)

In the PCM data interface method between the control station vocoder and the switching station, A first step of setting a channel value of DS0 assigned to each vocoder in a channel register in the PCM interface unit when setting up a call of each vocoder channel, and delivering a bit offset and a bit size to each vocoder; When the PCM data is transferred from the switching center to the vocoder after the first step, the second vocoder processing the corresponding bit by the bit size from the bits spaced apart by the bit offset from the start signal of the PCM data; In case of transmitting PCM data from each vocoder to the switching center, each vocoder transmits a bit of the bit size from the bits spaced apart by the bit offset from the PCM data transmission start signal to the corresponding PCM channel. PCM data interface method of the VOCODER characterized in that it comprises a step. The method of claim 1, The vocoder selectively accesses the PCM channel in units of 1,2,4,8 bits.