JP2006173756A - Communication method and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication method and a receiver by inserting a self-complementary sequence data to a data part of a communication frame comprising a preamble part, a header part, and the data part so as to perform synchronization detection and/or multipath detection. <P>SOLUTION: In the communication method and the receiver using the communication frame comprising the preamble part, the header part, and the data part 41, the communication frame includes the self-complementary sequence data 411 for the synchronization detection and/or multipath detection at a top of the data part 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication method and a receiver.

  In FIG. 1A, IEEE (Institute of Electrical and Electronics Engineers) 802.11 or the like uses the communication frame shown in FIG.

  The communication frame in FIG. 1A includes a preamble part 11, a header part 12, and a data part 13.

  For example, FIG. 1B shows a communication frame in FH PLCP (frequency Hopping Physical layer Convergence Procedure), which is one of the standards of IEEE 802.11.

  In the communication frame of FIG. 1B, the preamble part is composed of an 80-bit sync field (Sync 21) and a 16-bit start frame delimiter field (SFD 22). The preamble part is used to synchronize the transmitter and the receiver as in the Ethernet (registered trademark). The 80-bit sync field has a pattern of “010101... 01”, and the SFD is “0000 1100 1011 1101” of 16 bits, which means the end of the preamble.

  In the communication frame of FIG. 1B, the header (PLCP header) is composed of 12-bit PLW (PSDU Length Word) 23, 4-bit PSF (PLCP Signaling) 24, and 16-bit HEC (Header Error Check) 25. Has been. In the PLW, data having a length of PSDU (PLCP Service Data Unit) 26 is stored. This is because the PSDU 26 corresponding to the data part has a variable length (maximum 4095 bytes), so the transmitting side notifies the receiving side of the length by the PLW 23.

  The PSF 24 stores the speed used by the payload MAC frame. Thereby, 1 Mbps to 4.5 Mbps can be designated. The HEC 25 stores a 16-bit CRC for the contents of the header.

  Incidentally, the communication frame shown in FIG. 1 has a problem that data transmission / reception synchronization detection and / or multipath detection cannot be sufficiently performed.

  In addition, there is a problem that a set of 256 codewords that are standardized by international standards has a combination that is related to a self-complementary sequence but is not effectively used.

  The present invention has been made in view of the above problems, and the present invention inserts self-complementary sequence data into a data portion of a communication frame composed of a preamble portion, a header portion, and a data portion, and detects synchronization. An object of the present invention is to provide a communication method and a receiver capable of performing multipath detection.

  In order to solve the above problems, the present invention employs means for solving the problems having the following characteristics.

  The invention described in claim 1 is a communication method using a communication frame composed of a preamble part, a header part, and a data part. The communication frame is used for synchronization detection and / or at the beginning of the data part. Alternatively, it has self-complementary series data for multipath detection.

  According to a second aspect of the present invention, in the communication method according to the first aspect, the self-complementary sequence data is 256 {1, j, -1, -j} of length 8 used in IEEE802.11. It is characterized in that the codewords are two codewords in a self-complementary relationship.

According to a third aspect of the present invention, in the communication method according to the second aspect, when the two code words in the self-complementary relationship are S ₀ and S ₁ , the self-complementary sequence data is the code word S _0. has a front half portion of the composed code length 4, and a second half portion of the composed code length 4 based on the code word S ₁ based on,
The first half is
S ₀ , S ₀ , S ₀ , S ₀ ,
S ₀ , jS ₀ , -S ₀ , -jS ₀ ,
S ₀ , -S ₀ , S ₀ , -S ₀ , or S ₀ , -jS ₀ , -S ₀ , jS ₀ ,
The latter half is
S ₁ , S ₁ , S ₁ , S ₁ ,
S ₁ , jS ₁ , -S ₁ , -jS ₁ ,
S ₁ , -S ₁ , S ₁ , -S ₁ , or S ₁ , -jS ₁ , -S ₁ , jS ₁ ,
An interval between corresponding codewords in the first half and the second half is a predetermined interval.

  According to a fourth aspect of the present invention, in a receiver for receiving a communication frame composed of a preamble part, a header part, and a data part, self-complementary sequence data exists at the beginning of the data part of the received frame. In this case, synchronization detection and / or multipath detection is performed based on the self-complementary sequence data.

  According to a fifth aspect of the present invention, in the receiver according to the fourth aspect, the self-complementary sequence data is 256 {1, j, -1, -j} of length 8 used in IEEE802.11. It is characterized in that the codewords are two codewords in a self-complementary relationship.

According to a sixth aspect of the present invention, in the receiver according to the fifth aspect, when the two code words in the self-complementary relationship are S ₀ and S ₁ , the self-complementary sequence data is the code word S _0. has a front half portion of the composed code length 4, and a second half portion of the composed code length 4 based on the code word S ₁ based on,
From the sender
As the first half,
S ₀ , S ₀ , S ₀ , S ₀ ,
S ₀ , jS ₀ , -S ₀ , -jS ₀ ,
S ₀ , -S ₀ , S ₀ , -S ₀ , or S ₀ , -jS ₀ , -S ₀ , jS ₀ are transmitted sequentially,
As the latter half,
S ₁ , S ₁ , S ₁ , S ₁ ,
S ₁ , jS ₁ , -S ₁ , -jS ₁ ,
If S ₁ , -S ₁ , S ₁ , -S ₁ , or S ₁ , -jS ₁ , -S ₁ , jS ₁ are sent sequentially,
Matching with properties of (1, 1, 1, 1), (1, j, -1, -j), (1, -1, 1, -1) or (1, -j, -1, j) Using a filter, synchronization detection and / or multipath detection is performed from self-complementary sequence data.

  According to the present invention, it is possible to perform synchronization detection and / or multipath detection by inserting self-complementary sequence data into a data portion of a communication frame including a preamble portion, a header portion, and a data portion.

  FIG. 2 shows a communication system to which the present invention is applied. On the transmission side (A) of the communication system of FIG. 2, the frame of FIG. In FIG. 1B, the FH PLCP frame has been described, but the present invention is not limited to this and can be implemented. For example, HDLC (High-level Data Link Control) may be used.

  In the packetizer 32, when the amount of data that can be transmitted in a frame is exceeded, the transmission data is divided into packets. The RF unit 33 modulates the packet signal and converts it into a radio frequency signal. This radio frequency signal is transmitted from the antenna.

  On the reception side (B) of the communication system in FIG. 2, the signal transmitted from the transmission side device is received by the reception device 34 to obtain a baseband signal. The depacketizer 35 extracts data from the packet signal, and the continuous dataizer returns the divided data to the original.

  The transmitted / received signal may be encoded and / or encrypted.

  In the present invention, as shown in FIG. 3, the self-complementary sequence data 411 for synchronization detection and multipath detection is inserted at the beginning of the data portion 41 in the data portion of the frame packetized by the transmission side apparatus. . Therefore, the transmission data 412 is transmitted after the self-complementary sequence data 411.

  FIG. 4 shows an example of a signal receiving side device having the data portion of FIG. 4 includes a reception device 51, a depacketization device 52, a multipath removal device 53, a continuous data conversion device 54, and a synchronization detection and multipath detection device 55.

  A signal transmitted from the transmission side device is received by the reception device 51 to obtain a baseband signal. The depacketizer 52 extracts the data from the packet signal, the multipath remover 53 removes the multipath, and the multipath removed signal is converted into the original data by continuing the divided data in the continuous dataizer. Get the data (transmitted data). The synchronization detection and multipath detection device 55 performs synchronization detection and multipath detection from the synchronization detection and multipath detection self-complementary sequence data inserted at the beginning of the data portion, and synchronizes the depacketization device or the like. In addition, the multipath removal device 53 performs multipath removal.

  4 performs synchronization detection and multipath detection from the self-complementary sequence data for synchronization detection and multipath detection inserted at the beginning of the data part, but for synchronization detection and multipath detection. One of synchronization detection and multipath detection may be performed from the self-complementary sequence data for use.

  Next, the self-complementary series data for synchronization detection and multipath detection inserted at the beginning of the data part will be described.

  FIG. 5 shows a set of 256 codewords of international standards used in IEEE 802.11 or the like.

Each codeword in FIG. 5 is, for example, as shown in FIG.
S ₀ is 1, 1, 1, -1, 1, 1, -1, 1 and
jS ₀ is j, j, j, −j, j, j, −j, j,
-S ₀ is -1, -1, -1, 1, -1, -1, 1, -1,
−jS ₀ is −j, −j, −j, j, −j, −j, j, −j,
...
_S63 is j, -1, -1, j, -1, -j, j, 1
jS ₆₃ is -1, -j, -j, -1, -j, 1, -1, j,
-S ₆₃ is, -j, 1, 1, -j , 1, j, -j, is -1,
-Js ₆₃ is, 1, j, j, 1 , j, -1, 1, it is -j.

  FIG. 7 shows codewords as examples of codewords constituting a self-complementary sequence from among the 256 codewords.

{S ₀ , S ₁ } and {S ₂ , S ₃ } are self-complementary sequences.

That is, when the autocorrelation function (R ₀₀ ) of S ₀ is obtained, R ₀₀ = 1, ₀ , ₁ , ₀ , 3, ₀ , −1, 8, −1, ₀ , 3, ₀ , ₁ , ₀ , 1 • (1)
It becomes. Further, when the autocorrelation function (R ₁₁ ) of S ₁ is obtained, R ₁₁ = −1, 0, −1,0, −3,0,1,8,1,0, −3,0, −1,0 , -1 (2)
It becomes. Here, when the sum of the autocorrelation function (R ₀₀ ) of S _{0 and} the autocorrelation function (R ₁₁ ) of S ₁ is obtained,
R ₀₀ + R ₁₁ = 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 (3)
It becomes. According to this, since the sum of the autocorrelation function (R ₀₀ ) of S _{0 and} the autocorrelation function (R ₁₁ ) of S _{1 has} no side lobe other than the central bit, {S ₀ , S ₁ } Is a self-complementary series.

Similarly, when the autocorrelation functions (R ₂₂ and R ₃₃ ) of S ₂ and S ₃ are obtained and the sum of the two is obtained,
R ₂₂ = -1, 0, -1, 0, -3, 0, 1, 8, 1, 0, -3, 0, -1, 0, -1 (4)
R ₃₃ = 1, 0, 1, 0, 3, 0, −1, 8, −1, 0, 3, 0, 1, 0, 1 (5)
R ₂₂ + R ₃₃ = 0, 0, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 (6)
It becomes. According to this, {S ₂ , S ₃ } is a self-complementary series.

  Using this self-complementary sequence, synchronization between transmission and reception can be achieved.

That is, as shown in FIG. 3, synchronization data is inserted at the beginning of the data portion 13 of the communication frame of FIG. As the synchronization data, the code word S ₀ and the code word S ₁ shown in FIG. 8A can be used. The insertion position of the synchronization data is not limited to the beginning of the data portion 13. As long as the insertion position is clear in the data part 13, it may be anywhere. However, it is preferable to insert it at the beginning of the data portion 13 in order to perform processing according to the detected synchronization.

  Next, FIG. 8B shows a circuit for detecting synchronization using the synchronization detection signal shown in FIG.

8B includes a delay circuit 61 with a delay time T, a matched filter 62 for the code word S ₀ , a matched filter 63 for the code word S ₁ , and an adder 64. The matched filter functions as a time correlator.

Synchronization detection signal shown in FIG. 8 (A) is, when it is supplied to the input terminal 60, from the matched filter 62 of the code word S _0, the autocorrelation function of the code word S ₀ and codeword S ₀ and codeword S A cross-correlation function with ₁ is output. The cross-correlation function between codeword S ₀ and codeword S ₁ can be ignored with respect to the autocorrelation function of codeword S ₀ .

Further, from the matched filter 63 of the code word S _1, the cross-correlation function the autocorrelation function and the code word S ₀ of the code words S ₁ and the code word S ₁ is output. The cross-correlation function between codeword S ₀ and codeword S ₁ can be ignored relative to the autocorrelation function of codeword S ₂ .

The adder 64 adds the output of the matched filter 62 of the code word S ₀ and the output of the matched filter 63 of the code word S ₁ . Since the delay circuit 61 is inserted at the input of the matched filter 62 of the code word S ₀ , the adder 64 adds the output of the expression (1) and the output of the expression (2), and the expression (3) Output is obtained.

  Therefore, synchronization between transmission and reception can be achieved based on the position of the central bit in Equation (3). Note that the output of Expression (3) is output according to the multipath characteristics when multipath exists in the propagation path. Therefore, the multipath characteristic can be detected on the receiving side by the synchronization detection signal shown in FIG.

As the first half of the synchronization data, using S _0, as the second half portion, has been described an example using the S _1, as the first half of the synchronization data, using jS _0, -S ₀ or -js ₀ , JS ₁ , -S ₁ or -jS ₁ may be used as the latter half.

Further, as the data for synchronization, instead of the code word S ₀ and the code word S ₁ shown in FIG.
The code word S ₀ and the code word S ₁ shown in (A) can be used.

In synchronization data shown in FIG. 9 (A), 4 code words related to the code word S ₀ can be generated using the circuit shown in FIG. 10. Similarly, the four codewords related codewords S ₁ in FIG. 9 (A) can also be generated using the circuit shown in FIG. 10.

  Next, FIG. 9B shows a circuit for detecting synchronization using the synchronization detection signal shown in FIG.

9B includes a delay circuit 71, 76, 81, 86 having a delay time T, a delay circuit 73 having a time 24T, a delay circuit 78 having a time 16T, a delay circuit 83 having a time 8T, and a codeword-jS. ₀ of the matched filter 72, the matched filter 74 codewords -js _1, matched filter 77 codewords -S _0, the matched filter 80 codewords -S _1, matched filter 82 codewords jS _0, codeword jS ₁ matched filter 85, the matched filter 87 of the code word _{S 0,} and a matched filter 89, and the adder 75,79,84,88 codewords _{S 1.} Note that the matched filter functions as a time correlator as described above.

An example in which S ₀ , jS ₀ , -S ₀ , -jS ₀ is used as the first half of the synchronization data, and S ₁ , jS ₁ , -S ₁ , -jS ₁ is used as the second half. But
As the first half of the synchronization data,
S ₀ , S ₀ , S ₀ , S ₀ ,
Using S ₀ , -S ₀ , S ₀ , -S ₀ , or S ₀ , -jS ₀ , -S ₀ , jS ₀ ,
S ₁ , S ₁ , S ₁ , S ₁ ,
S ₁ , -S ₁ , S ₁ , -S ₁ , or S ₁ , -jS ₁ , -S ₁ , jS ₁ may be used.

  As described above, the synchronization data having the first half of the code length 4 configured based on the codeword S0 in FIG. 9A and the second half of the code length 4 configured based on the codeword S1 is used. In this case, the output of the synchronization detection can be four times that of the synchronization data shown in FIG.

  In addition, when multipath exists, synchronization data is received according to the multipath. Therefore, the multipath characteristic can be detected on the receiving side based on the synchronization data described above.

  Therefore, the synchronization data can also be used as multipath characteristic detection data.

  Although the best mode for carrying out the invention has been described above, the present invention is not limited to the embodiment described in the best mode. Modifications can be made without departing from the spirit of the present invention.

It is a figure for demonstrating the structure of a communication frame. It is a figure for demonstrating a communication system. It is a figure for demonstrating the data part of this invention. It is a figure for demonstrating the example of the receiving side of this invention. It is a figure for demonstrating the set of a code word (256 words). It is a figure for demonstrating the example of a codeword (8 bits). It is a figure for demonstrating the example of the codeword which comprises a self-complementary series. It is a figure for demonstrating a synchronous detection (the 1). It is a figure for demonstrating a synchronous detection (the 2). It is a figure for demonstrating a filter.

Explanation of symbols

11 Preamble part 12 Header part 13, 41 Data part
21 Sync
22 SFD
23 PLW
24 PSF
25 HEC
26 PSDU
31 Transmission data
32 packetizer 33 RF converter 34, 51 receiver 35, 52 depacketizer 36, 54 continuous data generator 411 synchronization detection and multipath detection data 412 transmission data
53 Multipath Removal Device 55 Synchronization Detection and Multipath Detection Device

Claims (6)

In a communication method using a communication frame composed of a preamble part, a header part, and a data part,
The communication method has a self-complementary sequence data for synchronization detection and / or multipath detection at the beginning of the data portion.   The self-complementary sequence data is two codewords having a self-complementary relationship among 256 {1, j, -1, -j} codewords of length 8 used in IEEE 802.11. The communication method according to claim 1. When the two codewords having the self-complementary relationship are S ₀ and S ₁ ,
The self-complementary sequence data has a first half of a code length 4 configured based on the codeword S ₀ and a second half of a code length 4 configured based on the codeword S ₁ .
The first half is
S ₀ , S ₀ , S ₀ , S ₀ ,
S ₀ , jS ₀ , -S ₀ , -jS ₀ ,
S ₀ , -S ₀ , S ₀ , -S ₀ , or S ₀ , -jS ₀ , -S ₀ , jS ₀ ,
The latter half is
S ₁ , S ₁ , S ₁ , S ₁ ,
S ₁ , jS ₁ , -S ₁ , -jS ₁ ,
S ₁ , -S ₁ , S ₁ , -S ₁ , or S ₁ , -jS ₁ , -S ₁ , jS ₁ ,
The communication method according to claim 2, wherein an interval between corresponding codewords in the first half and the second half is a predetermined interval. In a receiver that receives a communication frame composed of a preamble part, a header part, and a data part,
When self-complementary sequence data exists at the beginning of the data portion of the received frame,
A receiver that performs synchronization detection and / or multipath detection based on the self-complementary sequence data.   The self-complementary sequence data is two codewords having a self-complementary relationship among 256 {1, j, -1, -j} codewords of length 8 used in IEEE 802.11. The receiver according to claim 4. When the two codewords in the self-complementary relationship are S ₀ and S ₁ ,
The self-complementary sequence data has a first half of a code length 4 configured based on the codeword S ₀ and a second half of a code length 4 configured based on the codeword S ₁ .
From the sender
As the first half,
S ₀ , S ₀ , S ₀ , S ₀ ,
S ₀ , jS ₀ , -S ₀ , -jS ₀ ,
S ₀ , -S ₀ , S ₀ , -S ₀ , or S ₀ , -jS ₀ , -S ₀ , jS ₀ are transmitted sequentially,
As the latter half,
S ₁ , S ₁ , S ₁ , S ₁ ,
S ₁ , jS ₁ , -S ₁ , -jS ₁ ,
If S ₁ , -S ₁ , S ₁ , -S ₁ , or S ₁ , -jS ₁ , -S ₁ , jS ₁ are sent sequentially,
Matching with properties of (1, 1, 1, 1), (1, j, -1, -j), (1, -1, 1, -1) or (1, -j, -1, j) 6. The receiver according to claim 5, wherein synchronization detection and / or multipath detection is performed from self-complementary sequence data using a filter.

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