CN1152378A

CN1152378A - Device for optimal division of data into data blocks in time-division multiple access system

Info

Publication number: CN1152378A
Application number: CN 95193646
Authority: CN
Inventors: 克里斯托弗·莫罗
Original assignee: Alcatel Alsthom Compagnie Generale dElectricite
Current assignee: Alcatel CIT SA; Alcatel Lucent SAS
Priority date: 1994-05-20
Filing date: 1995-05-15
Publication date: 1997-06-18
Also published as: WO1995032557A1; FR2720207B1; EP0760183A1; AU2571195A; FR2720207A1

Abstract

Device for optimal division of data into data blocks transmitted in a radio system of the time-division multiple access (TDMA) type in which a dimensioning and distribution unit (18) in the transmitter is adapted to dimension the data block and distribute the data into different block areas according to the types of data received and the coding redundancy for each of these types, and a measuring unit (28) in the receiver for collecting the transmission channel quality measurements and transmitting them to the dimensioning and distribution unit (18) in the transmitter.

Description

In the time-division multiple address system in data block the device of optimized distribution data

The optimization of the error rate that the present invention relates in the wireless communication system to be run into, the device of optimized distribution data in the data block that relates in particular in the radio communications system to be exchanged.

Time division multiple access (TDMA) type cordless communication network provides terminal mobility to the user as a fundamental characteristics of GSM or DCS network.Change because the signal transmission conditions move with the user, this mobility causes the rapid variation of calling channel parameter.

In addition, distortion easily takes place in transfer sequence in transmission channel, and the main type of distortion is intersymbol interference, and this is because transmission code can transmit along the mulitpath in the transmission channel.If have the intersymbol distance of the difference of two paths at least greater than two consecutive transmissions, so, get a paths wherein sign indicating number will with get another next sign indicating number and produce and disturb than short path.

In order to regulate the rapid variation of parameter and intersymbol interference, receiver uses equalizer, but for making the equalizer operate as normal, the impulse response of necessary known transmission channel.

For reaching this purpose, beard and hair send a learn sequence of being made up of known code, and this sequence is different with the numeric data code that is about to send, and the latter is unknown for receiver end.Therefore, common measure is that this code block comprises in proper order for specific receiver provides a code block: the letter sign indicating number; Learn sequence; Next column letter sign indicating number, promptly learn sequence is positioned in the middle of the code block.

But probable bit error increases with the distance between sign indicating number and learn sequence.Therefore, not only must avoid constructing excessive block of information, and must optimize the data allocations in piece or the structure, because some data (as signaling data) are more responsive to the error code owing to transmission conditions than other data.

In view of this, the objective of the invention is to provide a kind of device, this device with payload as the function of different types of data to the sensitivity of error code, optimized distribution in the data block that in wireless communication system, exchanges.

The invention provides the device of optimized distribution different types of data in the data block that exchanges in the wireless communication system, the type wireless communication system comprises: a) by an encoder that the numerical data that sends is encoded, format and multi-path transmission unit and the transmitter that modulator is formed; B) demodulator of the modulating data that is sent from modulator by a reception, one go to format and multi-channel separative element, and the receiver formed of the decoder of a reduction number digital data.This device comprises fixed length (dimensioning) and the allocation units in the transmitter, the length that is used for the specified data piece, and the data type of conduct transmission reaches the function to every type of data decode redundancy, the section of implementation data in data block distributes, also comprise the measuring unit that is positioned at receiver, be used to collect and deliver to fixed length and the allocation units that are positioned at transmitter about the measurement result of propagation channel quality and with above-mentioned data.

Target of the present invention, purpose and other characteristic will describe in detail with reference to accompanying drawing below.Wherein:

Fig. 1 is given in the general type of the data block that exchanges in the wireless communication system;

It is the curve chart of the error rate of variable that Fig. 2 shows with the position in data block;

Fig. 3 provides the data block that a different types of data distributes with optimum way;

Fig. 4 is the block diagram of an embodiment of apparatus of the present invention.

As mentioned above, because the mobility of terminal causes the rapid variation of transmission conditions, so the data that received in must the cordless communication network to the GSM type are carried out equilibrium often.

This is that the block of information that exchanges in the network has the reason of form shown in Figure 1.It comprises a learn sequence SA and " payload ", and build and piece tail sign indicating number T.For avoiding far away excessively apart, " payload " places learn sequence SA both sides.

Learn sequence SA can form by 26, and each section payload can be formed by 57.But these length are also nonessential, and they depend primarily on the physical constraint of transmission channel.Usually, at first essentially seek a good learn sequence, then, the length of payload Cu as the length of SA, the noise function fixed length in addition of modulation code when, therefore just can be obtained the optimization length of payload in the application under the given criterion.

Such criterion can be embodied in and be positioned at the cell end sign indicating number and be no more than every yard given error rate.Every yard or every bit error rate (balanced back) are the functions of the position of sign indicating number in the unit, and its general form as shown in Figure 2.The error rate increases with the increase of distance curve intermediate distance.Therefore, as the function of the error rate that is not exceeded, the optimization length of piece can be determined at an easy rate by considering curve shown in Figure 1.

But must satisfy the constraint of professional efficient.The minimum data rate that must be transmitted causes the payload of some in each piece, and its size perhaps needs to surpass predetermined optimization length.

However, in all cases, it is favourable as different types of data the function of the sensitivity of transmission error code being distributed payload in piece.Insensitive sign indicating number or position are positioned over end, and more sensitive sign indicating number or position are near the center.Following situation constitutes the fine explanation to the problems referred to above:

The data of being protected by the error coded check sign indicating number: near the data bit centre, redundant digit is placed on end;

Asymmetric coding (the error coded check coding that is used for the GSM voice): in the middle of important position was placed on, other was placed on two ends;

Have the error coded check coding in the mechanism of duplication code: in the middle of data bit was placed on, redundant digit (being used to detect error code) was placed on two ends.Thereby data bit will contain still less error code still less replica code is arranged, so wireless channel will be utilized more effectively;

Signaling (signalling) in the piece: because signaling bit is very responsive to error code, place at their as close as possible centers, for example is right after after the learn sequence;

Consolidated traffic: suppose two kinds of mix of traffic (as sound and clear data) in a piece, not too the position of Ling Min business is placed on end (as sound), and the position of sensitive business is placed on middle (as clear data);

Be dispersed in the mass data by coding protection (when being used for GSM) in a plurality of: in the middle of more responsive position was placed on, not too responsive position was placed on end.

So, being illustrated in the data cell of Fig. 3, signaling-information (1 and 1 ') is placed on the both sides of learn sequence SA, and the sign indicating number (2 and 2 ') that relates to the sensitivity of clear data is placed on the both sides of signaling-information, and last not too responsive sign indicating number (3 and 3 ') is placed on end.

Fig. 4 is the block diagram of the device of the data in the optimized distribution data cell in one embodiment of the present of invention.

As shown in the figure, the data that are sent out in the frame have three classes: sound (V), clear data (D) and signaling (S).Data are encoded in channel encoder 10 at first to determine the redundant digit of every class data.These positions can only be parity bits, or the sign indicating number of detection and corrects bit errors.In case coding, information promptly are sent to format and multi-path transmission unit 12 block format and the multiplexing logic channel with regulation transmission.Such format and multi-path transmission unit are conventional, and suitable description can be found in the work " Telecomputing: transmit and deal with data in network " (Dunod published in 1987) of C.Macchi and J.P.Guilbert.Then, data block is added to modulation on the modulator 14, sends by transmitting antenna 16 at last.

In the described transmitter, the inventive system comprises a fixed length and allocation units in the above, to use sensitivity criterion specified data block length described above.Unit 18 also connects and interior section number and the relevant data of length thereof of data block, separates so that can correctly implement multichannel at receiving terminal.

Fixed length is connected with data input V, D and S with allocation units 18, so that therefrom extract relevant data, these data are: the data type numbering of input, can indicate by the relative priority level of the definite business of traffic conditions (promptly helping conversation) at peak period, and condition relevant with the quality of reception (signaling-information transfer ratio clear data is sensitiveer) and transmission delay condition.

The input of unit 18 also is connected to the output of encoder 10, receives the encoding scheme that adopts about each business or data type therefrom and to the quality requirement indication of clear data information and coding redundancy degree.

At last, unit 18 also receives the measurement result from receiver as described below.The indication that receives from the disparate modules of transmitter implements to measure length that the gained result makes that unit 18 can the specified data piece and the data of distributing each section with aforementioned optimization method with receiver.This information directly is sent to format and multi-path transmission unit by fixed length and allocation units.

Receiver receives the modulating data from antenna 20, sends into demodulator 22 demodulation.Demodulating data is by going format and multi-channel separative element 24 (description of such unit can be found in the mentioned in front work equally) processing, and unit 24 separation logic channels also are transported to channel decoder 26 with them.Channel decoder is reduced to corresponding sound (V), clear data (D) and signaling (S) with numerical data.

Measuring unit 28 forms a complete part of apparatus of the present invention, it links to each other with the output of input and demodulator to extract the measurement result of relevant propagation channel quality, links to each other to extract the measurement result of relevant different section (corresponding to data of different types) quality with the output of decoder 26.

In case carried out essential measurement, measuring unit 28 is sent to fixed length and allocation units 18 with above-mentioned measurement result through Return Channel 30.This channel can be directly with the channel that is used for from the receiver to the transmitter, transmitting the frequency band of payload data, or be positioned at channel outside the above-mentioned frequency band, for example be used for the channel of transmit traffic data.

Fixed length and allocation units can be realized by truth table, with the corresponding input numbering of input link as truth table.Such table can be set up in advance by simulation or on-the-spot test.Must be the output and the input parameter of function updating form with the measurement result that the measuring unit of receiver provides with software.These can both be at data processing equipment, as putting into effect effectively in the microcomputer.Yet very clear, the expert can realize not exceeding boundary of the present invention as principle of the present invention described above with various different modes.

Claims

1. be used for the device of optimized distribution data in the wireless communication system data block transmitted, such wireless communication system comprises:

A) transmitter comprises an encoder (10) that is used for the digital data coding that is transmitted, format and a multi-path transmission unit (12) and a modulator (14);

B) receiver comprises a demodulator (22) that is used for the data demodulates that sends from said modulator, and one is removed format and signal multi-channel separative element (24) and a decoder that is used to recover numerical data;

Said apparatus has following feature:

Above-mentioned transmitter also comprises the fixed length and the allocation units (18) that link to each other with the output of input and above-mentioned encoder, is applicable to the length of determining above-mentioned data block and is function distribute data in above-mentioned different sections with the received data type with above-mentioned every type coding redundancy degree;

Above-mentioned receiver also comprises a measuring unit (28), it links to each other with the output of input and above-mentioned demodulator and the output of above-mentioned decoder, collect the measurement result relevant with propagation channel quality, the dateout of above-mentioned measuring unit is delivered to the above-mentioned fixed length and the allocation units of above-mentioned transmitter.

2. device as claimed in claim 1, it is characterized in that above-mentioned fixed length and allocation units (18) are connected to the input of above-mentioned encoder (10), so as to obtain about the input data type of above-mentioned encoder numbering, about the mutual priority of above-mentioned data type, about the quality requirements that obtains at receiving terminal and about the indication of transmission delay condition.

3. device as claimed in claim 2, it is characterized in that above-mentioned fixed length and allocation units (18) receive the output of above-mentioned decoder (10), so that receive about encoding scheme that every type of data adopted, about the indication of clear data information and the desired quality of redundancy encoding.

4. as claim 1,2 or 3 described devices, it is characterized in that above-mentioned measuring unit (28) links to each other with the output of above-mentioned decoder (26), so that the quality of each section in the measurement data piece.

5. as any one described device of claim 1 to 4, it is characterized in that the measurement result that output provided of above-mentioned measuring unit (28) is transferred into above-mentioned fixed length and allocation units (18).

6. as the described device of above any one claim, it is characterized in that above-mentioned fixed length and allocation units (18) are truth tables with multichannel input, and be that the data processing equipment of the function software that upgrades above-mentioned truth table is managed by the result who is provided with above-mentioned measuring unit (28) is provided.