JP2725896B2 - Unique word detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a unique word (Unique Word), which is one of the key technologies in the field of time division multiplexing based access communication system to an improvement of the detection device.

[0002]

2. Description of the Related Art A conventional unique word detection apparatus for a soft-decision reception data sequence is disclosed in, for example, the document "OPTIMI".
ZED UW DETECTION FOR TDMA
COMMUNICATIONS "(B. Ekstr
▲ o ▼ m, Third International
Conference on DIGITAL SA
TELLITE COMMUNICATIONS, p
p. 265-272, Kyoto, November 1975)
It is described in. Hereinafter, the related art will be described with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of a conventional unique word detecting device . In the drawing, reference numeral 1 denotes a soft decision demodulator for receiving a received signal and outputting a soft decision received data sequence;
Reference numerals 2a, 2b, and 2c denote correlators that output correlation values based on the soft-decision received data sequence, 3a and 3b denote multipliers, and 4 denotes a correlation value output of the correlators 2a and 2b via the multipliers 3a and 3b. The adder 5 outputs the soft-decision correlation value by adding the correlation value output of the correlator 2c with the correlation value output of the correlator 2c. It is a determiner that performs.

Next, the operation will be described. The received signal is input to the soft-decision demodulator 1 and subjected to soft-decision demodulation, and a soft-decision received data sequence is output. Hereinafter, the soft-decision reception data sequence is a 3-bit data sequence having an integer value of 0 or more and 7 or less, and its data interval is T.

That is, assuming that the value of the soft-decision reception data output from the soft-decision demodulator 1 at time t = iT (i is an integer, the same applies hereinafter) is r _i , r _i ∈ ｛0, 1, 2, 3 , 4,
5, 6, 7｝. Also, assuming that the values of the most significant, second and least significant bits of r _i are a _i , b _i and c _i , respectively, a _i {0,1 }, b _i {0,1}, c _i ∈
{0, 1}, and r _i is given by a _i , b _i and c _i
i = 4a _i + 2b _i + c _i .

The most significant bit sequence {a _i } of the soft-decision received data sequence is input to the correlator 2a, where a correlation operation with the unique word is performed, and a correlation value is output. Similarly, the second-order bit sequence {b _i } and the least significant bit sequence {c _i } of the soft-decision reception data sequence are input to correlators 2b and 2c, respectively, and correlation values are output.

The length of the unique word sequence is L bits, and the value of the unique word sequence is u _j {0, 1} (j = 1,
, L) and the correlators 2a, 2 at time t = iT
The correlation values output from b and 2c are C _ai and C _bi , respectively.
And C _ci

## EQU1 ##

Next, the correlation value output from the correlator 2a is input to a multiplier 3a, and is multiplied by a weight corresponding to the most significant bit, that is, four. Similarly, the correlation value output from the correlator 2b is input to the multiplier 3b, and is multiplied by a weight corresponding to the second bit, that is, 2. Multiplier 3
The soft decision correlation value is obtained by adding the output of a, the output of the multiplier 3b, and the correlation value output from the correlator 2c by the adder 4. Assuming that the value of the soft decision correlation value at time t = iT is C _1i ,

(Equation 2) It is. That is, the soft-decision correlation value output from adder 4 is equal to the correlation value between the soft-decision received data sequence output from soft-decision demodulator 1 and the unique word.

The soft decision correlation value output from the adder 4 is input to a determiner 5. Further, a decision threshold value, which is a constant, is also input to the decision unit 5. Hereinafter, the value of the determination threshold value is a constant epsilon _1. The decision unit 5 _decides that a unique word has been received when a relationship of C _1i ≧ 7L−ε ₁ is established between the soft decision correlation value and the decision threshold value, and outputs a detection signal.

[0010]

The conventional unique word detection apparatus is configured as described above, and performs unique word detection using the received data sequence soft-decision demodulated as it is. However, in a communication system that performs soft decision demodulation, error control using an error correction code is generally performed, and soft decision demodulation is performed to decode an error correction code using soft decision data. Therefore, the soft decision data are made soft decision suitable for the decoding of the error correction code, the soft decision suitable for the unique word detection is not performed. Therefore, the conventional unique word detection apparatus performs unique word detection using soft decision data that is not suitable for unique word detection as it is, and there is a problem that the characteristic of unique word detection is degraded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a unique word detecting apparatus which realizes better unique word detecting characteristics even when soft decision data which is not suitable for detecting a unique word is used. The purpose is to obtain.

[0012]

The unique word detecting apparatus according to the present invention comprises a converter for converting a soft decision received data sequence into a nonlinear soft decision data sequence.

[0013]

In the present invention, the converter converts a soft decision received data sequence into a nonlinear soft decision data sequence suitable for unique word detection. By performing unique word detection using this nonlinear soft decision data sequence, unique word detection characteristics superior to the conventional unique word detection device are realized.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a unique word detecting device according to an embodiment of the present invention. In the drawing, the same parts as those in FIG. A converter 6 as a new configuration converts the soft decision received data sequence output from the soft decision demodulator 1 into a nonlinear soft decision data sequence and sends it to each of the correlators 2a, 2b, 2c. Unique word detection is performed using a data sequence.

Next, the operation will be described . The received signal soft decision demodulation is performed is input to the soft decision demodulator 1, the soft-decided received data sequence is outputted. The soft-decision reception data sequence is a 3-bit data sequence having an integer value of 0 or more and 7 or less, and its data interval is T. That is,
At time t = iT (i is an integer, the same applies hereinafter), the soft decision demodulator 1
Let r _i be the value of the soft-decision reception data output from
r _i ∈ {0, 1, 3, 4, 6, 7 }.

The soft-decision reception data sequence output from the soft-decision demodulator 1 is input to a converter 6 and converted, and a nonlinear soft-decision data sequence is output . It is assumed that the converter 6 has a conversion characteristic for converting 3-bit data into 3-bit data as shown in Table 1, for example.

[Table 1]

In this case, assuming that the value of the nonlinear soft decision data output from the converter 6 at the time t = iT is Z _i , Z _i
{0, 1, 2, 3, 4, 5, 6, 7}. Here, the top of Z _i, k _i # 2 and the least significant bit value, respectively, when m _i and n _i, i.e., k _i ∈ {0,
_{1}, m i ∈ {0,1} }, a n _i ∈ {0,1}, Z
_i is given by k _i , m _i and n _i , and Z _i = 4k _i + 2m _i +
expressed as n _i .

The most significant bit sequence {k _i } of the nonlinear soft decision data sequence output from the converter 6 is input to the correlator 2a, where a correlation operation with a unique word is performed, and a correlation value is output. Similarly, the second order bit sequence {m _i } and the least significant bit sequence {n _i } of the nonlinear soft decision data sequence
Are input to the correlator 2b and the correlator 2c, respectively, and the correlation values are output. The length of the unique word sequence is L bits, and the value of the unique word sequence is u _j {0,1}
(J = 1,..., L), and the values of the correlation values output from the correlators 2a, 2b and 2c at time t = iT are C _ki , C _mi and C _ni , respectively.

## EQU3 ##

[0019] Then, the correlation value output from the correlator 2a is input to the multiplier 3a, weight corresponding to the most significant bit, Sunawa Chi 4 is multiplied. Similarly, the correlation value output from the correlator 2b is input to the multiplier 3b, and is multiplied by a weight corresponding to the second bit, that is, 2. Multiplier 3
The soft-decision correlation value is obtained by adding the output of a, the output of the multiplier 3b, and the correlation value output from the correlator 2c with an addition value of 4. Let the value of the soft decision correlation value at time t = iT be C
Assuming _0i ,

## EQU4 ## That is, the soft-decision correlation value output from the adder 4 is equal to the correlation value between the nonlinear soft-decision data sequence output from the converter 6 and the unique word.

The soft decision correlation value output from the adder 4 is input to a determiner 5. Further, a decision threshold value, which is a constant, is also input to the decision unit 5. Hereinafter, the value of the determination threshold is defined as a constant ε ₀ . The determinator 5 determines that a unique word has been received when a relationship of C _0i ≧ 7L−ε ₀ holds between the soft-decision correlation value and the determination threshold, and outputs a detection signal.

As described above, in the above embodiment, the converter 6 converts a soft-decision received data sequence into a nonlinear soft-decision data sequence. Therefore, the conversion characteristic of the converter is set to a soft value that is not suitable for unique word detection. By setting the characteristic so that the decision data is converted to soft decision data suitable for unique word detection, even if the soft decision received data sequence is soft decision data not suitable for unique word detection, good unique word detection can be performed. The characteristics are realized.

In the above-described embodiment, the number of bits of the soft-decision reception data sequence output from the soft-decision demodulator 1 is set to 3 bits. However, other bits, for example, 4 bits, are used. Is also good.

In the above embodiment, the converter 6 converts 3-bit data into 3-bit data. However, the converter 6 performs other conversion, for example, converts 3-bit data into 4-bit data or 2-bit data. Bits or 4-bit data may be converted to 3 bits or 2 bits.

Further, in the above-described embodiment, the case of the unique word detecting device has been described. However, a synchronizing word detecting device used in the field of wired communication and wireless communication may be used, and the same effects as in the above-described embodiment can be obtained. .

[0025]

As described above, according to the present invention, since a converter for converting a soft-decision received data sequence into a nonlinear soft-decision data sequence is provided, the circuit is almost the same as the conventional unique word detection device. There is an effect that a unique word detection device that achieves better unique word detection characteristics by using soft decision data that is not suitable for unique word detection is obtained even though the scale is large.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a unique word detection device according to one embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of a conventional unique word detection device.

[Explanation of symbols]

 1 Soft Decision Demodulator 2a Correlator 2b Correlator 2c Correlator 3a Multiplier 3b Multiplier 4 Adder 5 Judge 6 Converter

Claims (1)

(57) [Claims] 1. A unique word detecting device for detecting a unique word included in a soft decision received data sequence, comprising a converter for converting the soft decision received data sequence into a nonlinear soft decision data sequence. Unique word detector.