阅读说明：本技术 发送装置、基站装置以及无线通信系统 (Transmission device, base station device, and wireless communication system ) 是由 佐佐木慧 佐野裕康 增田进二 于 2017-05-10 设计创作，主要内容包括：本发明的发送装置(10)具备：映射部(11),其通过对发送比特序列进行调制而生成调制码元；DSTBC编码部(12),其通过对调制码元进行差分空时分组编码而生成编码码元；码转换部(13),其对编码码元进行从多个转换处理中选择的所述转换处理；以及天线(16、17),它们发送转换处理后的编码码元。(A transmission device (10) of the present invention includes: a mapping unit (11) that generates a modulation symbol by modulating a transmission bit sequence; a DSTBC encoding unit (12) that generates encoded symbols by performing differential space-time block coding on the modulation symbols; a code conversion unit (13) that performs the conversion process selected from among a plurality of conversion processes on the code symbol; and antennas (16, 17) which transmit the converted code symbols.)

1. A transmission device, comprising:

A modulation unit that generates a modulation symbol by modulating a transmission bit sequence;

An encoding unit that generates an encoded symbol by performing differential space-time block coding on the modulation symbol;

A conversion unit configured to perform the conversion process selected from among a plurality of conversion processes on the code symbol; and

An antenna that transmits the coded symbols after the conversion processing.

2. The transmission apparatus according to claim 1,

The antenna is a plurality of antennas, and the antenna is a plurality of antennas,

selecting the conversion process to be performed on the code symbols for each of the antennas corresponding to the code symbols.

3. The transmission apparatus according to claim 2,

There are 4 said conversion processes predefined for each of said antennas,

The conversion unit performs the conversion process selected from the 4 conversion processes corresponding to the antennas on the code symbol.

4. The transmission apparatus according to claim 3,

The 4 conversion processes are: a process of outputting the encoded symbol as it is, a process of exchanging a real part and an imaginary part after inverting the sign of the imaginary part of the encoded symbol, a process of inverting the signs of the real part and the imaginary part of the encoded symbol, and a process of exchanging the real part and the imaginary part after inverting the sign of the real part of the encoded symbol.

5. A base station device, characterized in that,

The base station apparatus includes the transmission apparatus according to any one of claims 1 to 4.

6. The base station apparatus according to claim 5,

The base station device includes two of the transmission devices.

7. A wireless communication system including a base station apparatus and a control apparatus for controlling the base station apparatus,

The base station device includes a transmission device, and the transmission device includes:

A modulation unit that generates a modulation symbol by modulating a transmission bit sequence;

An encoding unit that generates an encoded symbol by performing differential space-time block coding on the modulation symbol;

A conversion unit configured to perform the conversion process selected from among a plurality of conversion processes on the code symbol; and

An antenna that transmits the coded symbols after the conversion process,

The control device transmits a signal indicating the conversion process selected by the conversion unit to the base station device.

8. The wireless communication system of claim 7,

The antenna is a plurality of antennas, and the antenna is a plurality of antennas,

the control device determines the conversion process selected by the conversion unit so that the phase difference between the plurality of antennas of the code symbol after the conversion process transmitted from the antenna is different for each of the base station devices having overlapping coverage areas.

9. The wireless communication system of claim 8,

The control means determines the conversion processing to be performed on the code symbol for each of the antennas.

10. The wireless communication system of claim 9,

There are 4 said conversion processes predefined for each of said antennas,

The control device determines the conversion process corresponding to the antenna from among the 4 conversion processes corresponding to the antenna.

11. The wireless communication system of claim 10,

The 4 conversion processes are: a process of outputting the encoded symbol as it is, a process of exchanging a real part and an imaginary part after inverting the sign of the imaginary part of the encoded symbol, a process of inverting the signs of the real part and the imaginary part of the encoded symbol, and a process of exchanging the real part and the imaginary part after inverting the sign of the real part of the encoded symbol.

12. The wireless communication system according to any of claims 8 to 11,

Combinations of information representing the conversion process of each of the antennas corresponding to the amounts of the plurality of the antennas are grouped into 4 groups according to the phase difference,

The control device assigns the combinations belonging to the different groups to the base station devices having the overlapping coverage areas, and determines the conversion processing corresponding to the antenna of the base station device based on the assigned combinations.

13. The wireless communication system according to any of claims 8 to 11,

The base station apparatus includes a plurality of the transmission apparatuses.

14. The wireless communication system of claim 13,

Combinations of information representing the conversion process of each of the antennas corresponding to the amounts of the plurality of the antennas are grouped into 4 groups according to the phase difference,

The control device assigns the combinations belonging to the different groups to the transmission devices of the base station devices having the overlapping coverage areas, and determines the conversion processing corresponding to the antenna of the base station device based on the assigned combinations.

Technical Field

The present invention relates to a transmitter apparatus, a base station apparatus, and a wireless communication system that perform transmission by a Differential Space-Time Block Coding (DSTBC) scheme.

Background

In wireless communication, as a technique for preventing communication performance degradation due to fading, a diversity technique is used in which transmission is performed using a plurality of transmission paths having different transmission path characteristics. For example, as an example of a transmission diversity technique in which a transmitting side performs transmission using a plurality of antennas, there is a STBC method in which a plurality of orthogonal sequences are generated by Space-Time block coding (STBC) and each sequence is transmitted via different antennas. In the STBC scheme, the receiving apparatus can realize full diversity (full diversity).

in the STBC scheme, a plurality of symbols (symbols) are processed as 1 block. In general, in the STBC scheme, the number of antennas corresponds to the number of symbols to be processed as 1 block. For example, when the number of antennas is 2, 1 block is composed of 2 symbols in the STBC scheme. In the STBC scheme, the reception apparatus needs to estimate the propagation path information in order to demodulate a received signal, but can obtain an effect of diversity by the STBC scheme.

Further, as a method that does not require estimation of transmission path information, non-patent document 1 discloses a DSTBC method that performs differential coding in units of blocks in the STBC method. For example, in the DSTBC transmission with the number of antennas set to 2, 2 × 2 matrices are generated with 2 symbols as 1 block, and differential encoding is performed between matrices of 2 consecutive blocks. In the DSTBC method, the receiving apparatus generates a 2 × 2 matrix using the received 2 symbols, and performs demodulation by performing differential decoding between matrices of 2 blocks.

Disclosure of Invention

Problems to be solved by the invention

In a wireless communication system in which a plurality of base stations are provided to provide communication between the base stations and a mobile station, it is desirable to eliminate an area in which the mobile station cannot receive a signal transmitted from the base station. Therefore, each base station is provided so that the communication areas of the base stations, that is, the ranges in which signals transmitted from the base stations can be received overlap. Therefore, when the same signal is transmitted from a plurality of base stations at the same frequency, there is a problem that the power of the received signal is reduced, that is, so-called beat interference occurs in the mobile station located in a place where the communication areas overlap, because the received signals are combined in opposite phases, thereby reducing the communication performance.

In addition, in a wireless communication system, it is desired to cover a range in which communication is provided with a smaller number of base stations by enlarging a communication area of one base station. As a method of expanding the communication area of one base station, it is conceivable to increase the number of transmission antennas. However, the transmission diversity technique based on the DSTBC method has the following problems: when the number of antennas is increased, the number of symbols included in 1 block, that is, the number of rows and columns of the generated matrix, increases, and the amount of processing increases exponentially.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a transmission device capable of suppressing a decrease in power of a received signal even when the same signal is transmitted from a plurality of base stations at the same frequency.

means for solving the problems

In order to solve the above problems and achieve the object, a transmission device according to the present invention includes: a modulation unit that generates a modulation symbol by modulating a transmission bit sequence; and an encoding unit that generates a code symbol by performing differential space-time block coding on the modulation symbol. The transmission device of the present invention further includes: a conversion unit that performs a conversion process selected from among a plurality of conversion processes on the code symbol; and an antenna that transmits the code symbol after the conversion processing.

Effects of the invention

The transmission device of the present invention has the following effects: even when the same signal is transmitted from a plurality of base stations at the same frequency, it is possible to suppress a decrease in the power of the received signal.

Drawings

Fig. 1 is a diagram showing a configuration example of a transmission device according to embodiment 1.

Fig. 2 is a diagram showing a configuration example of a receiving apparatus according to embodiment 1.

Fig. 3 is a diagram showing a processing circuit of embodiment 1.

Fig. 4 is a diagram showing a configuration example of a processing circuit including a processor according to embodiment 1.

Fig. 5 is a flowchart showing an example of a processing procedure of the transmission device according to embodiment 1.

fig. 6 is a diagram showing the arrangement of signal points in QPSK of embodiment 1.

FIG. 7 shows slave a of embodiment 1_k、b_k、c_k、d_kConversion to e_k、f_k、m_k、n_kAn example of the rule of (1).

FIG. 8 shows slave a of embodiment 1_k、b_k、c_k、d_kConversion to p_k、q_k、u_k、v_kAn example of the rule of (1).

Fig. 9 is a diagram showing an example of a wireless communication system according to embodiment 1.

Fig. 10 is a diagram showing an example of grouping of modes in embodiment 1.

Fig. 11 is a diagram showing a configuration example of a wireless communication system according to embodiment 2.

Fig. 12 is a diagram showing a configuration example of a base station apparatus according to embodiment 2.

Detailed Description

Hereinafter, a transmitter apparatus, a base station apparatus, and a wireless communication system according to embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments.