KR960014408B1 - Multi-access transmitter using prime code - Google Patents

Abstract

The method includes the steps of; modulating a block data to a M scale orthogonal sequence using binary scale orthogonal sequence, modulating a pulse position using a prime code, receiving a data signal and controlling a pulse wave, demodulating a pulse wave using the prime code, abstracting determinating variables according to each symbol using the binary scale orthogonal sequence, selecting a maximum value in the binary scale orthogonal sequence, and recovering a data by using a selecting the maximum value.

Description

M orthogonal code modulation method using prime code and multiple access transceiver using the same

1 is a schematic block diagram showing the overall configuration of a M-coded orthogonal code modulation multiple access system using the decimal code of the present invention.

2 is a schematic block diagram showing an apparatus for transmitting a multiple access system of the present invention.

3 is a schematic block diagram showing a receiving apparatus of a multiple access system of the present invention.

4 is a waveform of a data signal indicating that a signal is modulated by a spread spectrum signal system.

5 is a frequency spectral diagram of narrowband and wideband signals for use of frequency superposition.

6 is a waveform diagram showing a change in pulse position by the pulse position modulation method using the decimal code.

7 is a waveform diagram of pulses modulated by the M orthogonal code modulation using a binary orthogonal sequence.

* Explanation of symbols for main parts of the drawings

21: binary orthogonal sequence selector 22: pulse generator

23: pulse position modulator 24: decimal code generator

31: pulse waveform correlator 32: timeslot selector

33: decimal code generator 34: accumulator

35: maximum value selector sw: chip time switch

[Field of Invention]

The present invention relates to a signal modulation method for wideband multiple access used in cellular mobile communication, and a transmission / reception apparatus using the signal.

More specifically, a signal modulation method for broadband multiple access, in which a plurality of users can transmit voice (voice data after being lumped) or data information using the same frequency band simultaneously, and a plurality of users can use the modulated signal. It relates to a system capable of transmitting and receiving.

[Background of invention]

Due to the explosive demand for wireless communication, the shortage of radio resources is on the rise. That is, since the number of consumers increases exponentially compared to the limited radio resources, there is a problem of waiting for a long time for a call or communication failure in a time when wireless communication demand is concentrated at a time. Therefore, various communication methods are being developed to more efficiently use limited radio resources.

One of these is the Code Division Multiple-Access method. The code division multiple access is a method of simultaneously connecting a plurality of signals in a frequency band having a predetermined size using a spread spectrum communication method.

The code division multiple access scheme developed for the conventional cellular mobile communication mainly uses a spread spectrum signal, and to some extent, provides a high degree of frequency utilization capability to a large number of users.

4 shows that the signal is modulated by the spread spectrum signal method. When the binary data waveform d (t) signal is encoded by a code sequence (pseudo orthogonal sequence) c (t) that changes very rapidly, the signal spectral region of the original data signal is spread to become a wideband signal. This wideband output signal s (t) is called a direct spread type spread spectrum signal.

In particular, when the processing gain of the system in the communication method is relatively small, the implementation of the transmission and reception device was relatively easy. However, in the case of a narrowband code division scheme with low processing gain, there is a limit to using the frequency band efficiently in response to the explosive demand of consumers.

On the other hand, Spectrum Overlay technology is being developed to overcome the deepening shortage of radio resources and to solve the frequency allocation problem expected in personal mobile communication services. The frequency overlapping technique is a technique for transmitting a wideband signal by overlapping a frequency band in which a narrowband signal exists. In other words, since the same frequency band is transmitted at the same time, two signals, a narrowband signal and a wideband signal, can be used more effectively.

This frequency superposition technique should be such that the power spectral density of the wideband signal is sufficiently low that the influence on the spectral density function S _d (f) ((a) of FIG. 5) of the narrowband signal can be neglected. The quadrature orthogonal signal using the decimal code is obtained as a wideband signal and has a sufficiently low density S _s (f) of the power spectrum as shown in FIG.

However, the wideband code division multiple access method using the spread spectrum signal using the frequency superposition technique has a relatively large processing gain of the system, but there are many problems to be solved in implementing the system.

In order to solve the above problems, the present inventors have come to the present invention which combines a pulse position modulation scheme using a decimal code and an M-ary quadrature modulation scheme using a binary orthogonal sequence.

[Purpose of invention]

It is an object of the present invention to provide an M-coded orthogonal code division method using a decimal code that is easy to realize for efficient use of limited radio wave resources.

Another object of the present invention is to provide a M-ary orthogonal code division method using a decimal code that can be applied as a frequency overlapping technique.

It is another object of the present invention to provide a multiple access transmission / reception apparatus using the M binary orthogonal code division method using the decimal code for cellular mobile communication.

It is still another object of the present invention to provide a M-ary orthogonal code division method using a decimal code having excellent transmission error performance compared to a narrowband code division multiple access method using a conventional spread signal.

It is still another object of the present invention to provide a multiple access transceiver that is more efficient than a narrowband multiple access transceiver using a conventional spread spectrum signal.

[Summary of invention]

The present invention for achieving the above object includes a method for generating an M binary orthogonal signal using a decimal sign and a binary orthogonal signal. The modulated signal according to the present invention uses a prime code and a binary orthogonal sequence, modulates voice data or data using a binary orthogonal sequence, and modulates the modulated signal using a decimal code. . The modulated signal is then demodulated using a decimal sign at the receiving device and then demodulated at the accumulator to finally restore the data.

In addition, the multiple access transmission and reception apparatus according to the present invention; A transmission device comprising a binary orthogonal sequence selector 21, a pulse generator 22, a decimal code generator 23, and a pulse position modulator 24; And a receiver comprising a pulse waveform correlator 31, a switch sw, a decimal code generator 33, a time slot selector 32, an accumulator 34, and a maximum value selector 35. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[Description of Specific Example of the Invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal modulation method for broadband multiple access used in cellular mobile communication, and to a transmission / reception apparatus using the signal, wherein a plurality of users simultaneously use the same frequency band for voice (sampled voice data) or data information. The present invention relates to a signal modulation method for wideband multiple access, which can be transmitted, and to a system that can be transmitted and received by a plurality of users using the modulated signal. In addition, the signal modulation method according to the present invention has the advantage that can be applied as a frequency superposition technology.

Before describing the present invention, a pulse position modulation scheme using a decimal sign and an M-ary quadrature modulation scheme using a binary orthogonal sequence will be briefly described.

As shown in FIG. 6, the pulse position modulation method using a decimal code is a method of modulating the position of a pulse using a decimal code sequence C _j of a pulse waveform w (t) generated in a period T _f . In this way, a pulse position mcdulation (PPM) signal that distinguishes a pulse signal is obtained. This PPM signal corresponds to a sign and a signal.

In addition, the M-orthogonal modulation using a binary orthogonal sequence modulates an input signal by a Hadamard matrix. 7 shows examples of signals generated when M = 8, and each sequence is orthogonal to each other, and the M block orthogonal to one-to-one correspondence with the input block signal log ₂ M = 3 bits of data. Signal (this will be explained in detail later).

The modulated signal according to the present invention uses the above-described prime code and binary orthogonal sequence, and firstly modulates voice data or data information using a binary orthogonal sequence, and then converts the primary modulated signal into a decimal code. Second order modulation. The modulated signal is then demodulated first using a decimal sign at the receiving device and again demodulated at the accumulator.

Shown in FIG. 1 is a schematic block diagram of an M-coded orthogonal code division multiple access system using the decimal code of the present invention. As shown, a number of quadrature quadrature signal modulators are connected to generate quadrature quadrature coded signals to provide orthogonality between each signal to eliminate mutual interference, and each quadrature signal modulator is composed of transmission delay and channel noise. The total number of multiple access transmission lines moves. The modulated signal transmitted through the transmission path is subjected to signal processing at the same time while excluding mutual interference between multiple overlapped user signals of the same frequency and time zone in the M-orthogonal signal demodulator and delivered to each user.

₂ is a block diagram of a transmitting apparatus for modulating 사용자 k user data transmitted in blocks of log ₂ M bits. The transmitter includes a binary orthogonal sequence selector 21 for selecting a corresponding binary orthogonal sequence h _i from ＃k user data transmitted in blocks of log ₂ M bits, and a pulse generator for generating T _f periodic pulses. (22), the pulse position which modulates the position of the signal by adding the signals of the decimal code generator 23 which generates the decimal code by the selected decimal number P, and the signalized decimal code generator 23 of the pulse generator 22; It consists of a modulator 24.

The user's data is divided into blocks of log ₂ M bits, and a binary orthogonal sequence corresponding to each bit block is selected by the binary orthogonal sequence selector 21. The binary orthogonal sequence is then designed using the Hadamare matrix, which is

For example, if M = 8

Becomes The binary orthogonal sequence hi generated as described above is orthogonal to each other and corresponds to log ₂ M = 3 bits of data and becomes a M orthogonal signal. That is, the data and the orthogonal signal correspond as follows.

7 shows an example of a binary orthogonal sequence h _i (i = 0, 1, 2, 3, ... 7), where (a) is h ₀ (, (b) is h ₁ ) and (c) show the pulse waveforms of the orthogonal signal in the case of h ₇ , respectively.

The M × M Hadamard matrix HM obtained as described above is transformed into a matrix H _M ^ext of M binary orthogonal sequences of length N _S = 2LM (L is an integer) (-1) ^l-1 (1 = 1, Multiply the coefficients of 2, 3,… 2L) by H _M to obtain the following matrix:

Accordingly, blocks of user data select and output corresponding sequences among M row vectors, that is, binary orthogonal sequences, of the H _M ^ext matrix. In this case, the coefficient selection of (-1) ^l-1 is considered to reduce the influence of mutual interference of other signals by setting the average DC signal value of binary sequences to zero. The output signal h _mj : 0 ≦ j ≦ N _s −1 of the binary orthogonal sequence selector 21 is modulated in combination with the pulse w (t) generated in the frame period T _f . Here, the binary orthogonal sequence output signal becomes the coefficient of the pulse w (t) and generates an M-orthogonal orthogonal signal. This output signal is given by the following equation:

This M binary quadrature output signal is input to the pulse position modulator 24. The pulse position modulator 24 serves to change the position of the pulse by using the kth user's own decimal code (P) in order to suppress mutual interference with other signals in the M-orthogonal signal of a specific kth user. .

The unique decimal code (C _j ^(k) : 0 ≦ _j ≦ N _s −1) of the k-th user is generated by the decimal code generator 23. At this time, each pulse position is changed within the range of the decimal code (0 ≦ C _{j (k)} ≦ N _s −1). The N value is also given as the ratio of T _f to the width of the pulse T _c , that is, an integer of N = T _f / T _c . The output signal of the k-th user thus generated is as follows.

The pulse w (t) used here is a relatively narrow single-cycle (mono-cycle) pulse, a signal having a bandpass spectrum and has a transmission bandwidth of Tc-1.

3 shows a receiving device which operates in correspondence with the transmitting device of FIG. The receiver of the present invention comprises a pulse waveform correlator 31 which cross-correlates between a received signal and a pulse waveform to generate an output signal, and a switch for sampling a specific pulse energy among signals passing through the pulse waveform correlator 31 ( sw), a decimal code generator 33 generating essentially the same decimal code P as the decimal code generator of the transmitter, a time slot selector 32 for passing only a specific signal, and a time slot selector 32 An accumulator 34 accumulates and outputs a desired output value among the passed signals, and a maximum value selector 35 which selects a symbol giving a maximum value from the output of the accumulator 32 and makes a symbol decision.

The signal input to the pulse correlator 31 is a modulated signal transmitted from the pulse position modulator 24 of FIG. This modulated signal passes through a pulse waveform correlator 31 which cross-correlates the received signal with the pulse waveform and outputs the signal. At the same time, the correlation of the pulse waveforms is synchronized to obtain pulse energy ± EP, which is as follows:

The signal output from the pulse waveform correlator 31 is input to a switch sw used as a chip time T _c switchgear. The switch sw is a switch that opens and closes the chip time T _c periodically to sample a correlation value of pulse energy corresponding to ± E _p in a signal passing through the pulse waveform correlator 31.

The sampled signal is input to the next time slot selector 32. The time slot selector 32 is a pulse position modulated signal proportional to a code value (0 ≦ C _j ^(k) ≦ Ns−1) in a decimal code sequence {C _j ^(k) } assigned to each user in a transmitting apparatus. It is to restore. Since there is a pulse in the time slot corresponding to C _j ^(k) , the receiver selectively selects the time slot in C _j ^(k) and passes only the desired signal. That is, in order to detect a signal of the k-th user, a decimal code unique to the k-th user is generated according to the frame clock, and the code (0 ≦ C _j ^(k) ≦ N _s −1) generated in the T _f period is used. The corresponding time slot will be selected. In this case, since the pulse in the signal of the k-th user exists on the time slot, the sampled correlation value of the desired pulse (xj: 0 ≦ j ≦ N _s −1), that is,

You can optionally output Therefore, mutual interference with other signals is effectively eliminated in this process.

The decimal code C _j ^(k) is generated in the decimal code generator 33, which is essentially the same as the decimal code generator of the transmitting apparatus of FIG. 2, and is assigned to the unique decimal assigned to each user. To generate a decimal sign. The signal passing through the time slot selector 32 is input to the accumulator 34. The accumulator 34 accumulates an output value of a signal passing through the time slot selector 32 and outputs the result every symbol time. At this time, when an unwanted signal is input, the accumulation of the output value of the signal is relatively small, so that the desired signal and the unwanted signal can be distinguished according to the magnitude of the accumulation value. Determinants {z _m 1 corresponding to each symbol using M binary orthogonal sequences {h _mj O≤j≤N _s -1} {1≤m≤M} to demodulate the M-ary signal of a specific kth user ≤ _m ≤ M} is extracted through the accumulator, where z _m is:

A plurality of cumulative values that have passed through the accumulator 34 are again input at the maximum value selection 35. The maximum selector 35 selects a symbol giving the maximum value among the signals output from the accumulator 34 and makes a symbol decision. The maximum selector 35 selects the corresponding symbols L i {1, 2, 3,... , M},

Is determined as the actual transmitted M-ary signal of the k-th user. Thereafter, the data block of the log ₂ M-bit single user of the k-th user is sequentially recovered from the demodulated M-ary signal.

As described above, the present invention allows a plurality of users to connect a channel in the same frequency band and the same time zone to transmit voice or data information while effectively excluding interference.

In addition, when the width (T _c ) of a single cycle pulse is sufficiently narrow, the transmission bandwidth given by T _c -1 becomes large enough to transmit and receive a single cycle pulse. Therefore, when a wideband signal uses a low spectral power density characteristic, Channels can be shared so that radio resources can be used efficiently.

Furthermore, the wideband multiple access signal designed in the present invention is modulated using a single cycle pulse, compared to the conventional spread spectrum signal of a modulated transmission using an RF carrier, and thus, a real wideband multiple access transmission / reception system. This makes it easier to implement. In addition, it can be used as a signal for broadband multiple access in the future personal portable communication.

Although the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that modifications and variations can be made within the spirit and scope of the invention, and such variations or modifications are limited by the appended claims. You must lose.

Claims (4)

Modulating the received log ₂ M-bit block data into M binary orthogonal sequence using a binary orthogonal sequence; Modulating a pulse position of the modulated data signal using a decimal sign; Receiving the pulse position modulated data signal and correlating a pulse waveform; Demodulating the correlated pulse waveform using a decimal sign; Extracting a decision variable corresponding to each symbol from the demodulated signal using a binary orthogonal sequence; Selecting a maximum value from the extracted decision variable; And restoring data from the selected maximum value; M binary orthogonal code modulation method using a prime code, characterized in that consisting of. The method of claim 1, wherein the step of modulating the input log ₂ M-bit block data into an M orthogonal sequence using a binary orthogonal sequence is modulated using a Hadamard matrix. M-ary orthogonal code modulation. The method of claim 1, wherein the M-Orthogonal code-modulated signal is a wide-band signal having a low frequency spectrum density. A binary orthogonal sequence selector 21 for selecting a particular binary orthogonal sequence F _i , a pulse generator 22 for generating T _f periodic pulses, and a decimal code generator 23 for generating a fractional code by the selected decimal number P And a pulse position modulator (24) which modulates the position of the signal by summing the signal of the pulse generator (22) and the signal of the decimal code generator (23); A pulse waveform correlator 31 which cross-correlates between a received signal and a pulse waveform to generate an output signal, a switch sw for sampling a specific pulse energy among signals passing through the pulse waveform correlation 31, and the transmitting device A decimal code generator 33 for generating essentially the same fractional code as a decimal code generator of a time slot selector 32 for passing only a specific signal, and a desired output value of the signals passed through the time slot selector 32 is accumulated and outputted. And a receiver comprising an accumulator 34 and a maximum selector 35 that selects a symbol giving a maximum value from an output of the accumulator 32 and makes a symbol decision. .