CN101567771B - Data transmission method and terminal - Google Patents

Abstract

The invention discloses a data transmission method, which comprises the following steps: the base station sends a first data matrix S to the terminal⁽⁰⁾(ii) a The terminal performs space-time coding and decoding on the first data matrix to generate a first decoding result

And sending a first retransmission request to the base station if the first decoding result does not pass the check; the base station responds to the first retransmission request and sends a second data matrix S to the terminal^(odd)(ii) a The terminal performs space-time coding and decoding on the second data matrix to generate a second decoding result

And performing joint space-time coding decoding on the first data matrix and the second data matrix to generate a first joint decoding result

And a second joint decoding result

And the terminal combines the first decoding result, the second decoding result, the first joint decoding result and the second joint decoding result to generate a first combined result. By the invention, higher signal-to-noise ratio gain can be obtained under the condition of a slow fading channel or a quasi-static channel. The invention also discloses a terminal.

Description

Data transmission method and terminal

Technical Field

The present invention relates to the field of communications, and in particular, to a data transmission method and a terminal.

Background

A Hybrid Automatic Repeat Request (HARQ) technology is a transmission Error control mechanism used by combining an ARQ (Automatic Repeat Request) technology and a Forward Error Correction (FEC) technology. The HARQ technique can not only utilize the redundancy coding gain but also obtain the retransmission combining gain. The HARQ technology is applied to a Multiple Input Multiple Output (MIMO) system, and has a greater potential to improve the reliability of the system and the throughput of transmission. However, simply applying HARQ to a MIMO system with a single antenna application, i.e. simple retransmission, cannot fully utilize the advantages of spatial diversity of multiple antennas, and thus has the potential to further improve system performance.

In the 802.16e standard, HARQ mechanisms of the MIMO system are divided into four types, which are: chase combining MIMO HARQ (MIMO Chase HARQ), incremental redundancy MIMO HARQ (MIMO IR HARQ), Convolutional encoded incremental redundancy MIMO HARQ (MIMO IR HARQ for conditional Code), and space-time encoded MIMO HARQ (MIMO STC HARQ). The MIMO Chase HARQ is Chase combining, and its mechanism is to generate only one version of coded packet, and the content of each transmission is completely the same. MIMO IR HARQ is incremental redundancy, and is generated into four sub-packets, the first sub-packet sent comprises all information bits and a small amount of redundancy, and the rest 3 sub-packets are sent during retransmission, and the information contained in the sub-packets is redundant information. MIMO IR HARQ for conditional Code is incremental redundancy for Convolutional coding. MIMO STC HARQ is Space Time Coding (STC) based HARQ, and its transmission mechanism is as follows:

after receiving each transmission packet, the terminal performs relative coding according to the space-time coding methodThe maximum likelihood decoding is carried out on the transmission packets received in two adjacent times to solve the transmission code S₁，S₂Or S₁，S₂，S₃，S₄To achieve full transmit diversity as determined by the number of transmit antennas. Furthermore, the code streams decoded by every two adjacent transmissions are combined, so that the signal-to-noise ratio gain can be obtained.

The MIMO STC HARQ scheme is designed for burst (Blast) multi-antenna transmission mode. For the space-time coding transmission mode, that is, the a matrix when the transmitting antenna is 2 in 8021.6e, and the A, B matrix when the transmitting antenna is 4, only the HARQ mode is specified to be Chase Combining (CC) or Incremental Redundancy (IR).

The transmission A matrix when the number of the transmitting antennas is 2 is as follows: $A=\left[\begin{array}{cc}{S}_1& -{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_2^{*}\\ S_2& {\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2008100955159E00011.png,S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*}\end{array}\right].$

the transmission a matrix when the number of the transmission antennas is 4 is: $A=\left[\begin{array}{cccc}{S}_1& -{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_2^{*}& 0& 0\\ S_2& {\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2008100955159E00011.png,S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*}& 0& 0\\ 0& 0& S_3& -S_4^{*}\\ 0& 0& S_4& {\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_3^{*}\end{array}\right].$

the transmission B matrix when the number of the transmitting antennas is 4 is as follows: $B=\left[\begin{array}{cccc}{S}_1& -{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_2^{*}& S_5& -{\mathrm{<figure-callout\; id="7"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_7^{*}\\ S_2& {\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="S2008100955159E00011.png,S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_1^{*}& S_6& -{\mathrm{<figure-callout\; id="8"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_8^{*}\\ S_3& -S_4^{*}& S_7& {\mathrm{<figure-callout\; id="5"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_5^{*}\\ S_4& {\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_3^{*}& S_8& {\mathrm{<figure-callout\; id="6"\; label="S"\; filenames="S2008100955159E00021.png"\; state="\{\{state\}\}">S</figure-callout>}}_6^{*}\end{array}\right].$

for the MIMO Chase HARQ mode, the MIMO Chase HARQ mode is only limited to carry out space-time decoding in single transmission, and the signal-to-noise ratio gain is obtained by combining retransmission for multiple times. This approach does not take advantage of the diversity gain that exists between the two transmitted codes, and thus has the potential to further improve performance.

Disclosure of Invention

In view of one or more of the above problems, the present invention provides a data transmission method and a terminal, so as to further improve the HARQ performance of a MIMO system by fully utilizing the diversity gain between two MIMO transmissions.

The data transmission method according to the embodiment of the invention comprises the following steps: the base station sends a first data matrix S to the terminal⁽⁰⁾(ii) a The terminal performs space-time coding and decoding on the first data matrix to generate a first decoding resultAnd sending a first retransmission request to the base station if the first decoding result does not pass the check; the base station responds to the first retransmission request and sends a second data matrix S to the terminal^(odd)(ii) a The terminal performs space-time coding and decoding on the second data matrix to generate a second decoding resultAnd performing joint space-time coding decoding on the first data matrix and the second data matrix to generate a first joint decoding result

And a second joint decoding result

And the terminal combines the first decoding result, the second decoding result, the first joint decoding result and the second joint decoding result to generate a first combined result.

The terminal combines the first decoding result, the second decoding result, the first joint decoding result and the second joint decoding result by one of the following methods:

$S=\frac{1}{4}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+{{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)}),$ $S=\frac{1}{3}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+\frac{1}{2}({{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)})).$

the data transmission method according to the embodiment of the present invention may further include the steps of: under the condition that the first synthesis result does not pass the verification, the terminal sends a second retransmission request to the base station; the base station responds to the second retransmission request and sends a third data matrix S to the terminal^(even)Wherein the third data matrix is the same as the first data matrix; the terminal performs space-time coding and decoding on the third data matrix to generate a third decoding result

And performing joint space-time coding and decoding on the second data matrix and the third data matrix to generate a third joint decoding result

And a fourth joint decoding resultAnd the terminal pair is secondAnd combining the decoding result, the third combined decoding result and the fourth combined decoding result.

The terminal combines the second decoding result, the fourth decoding result, the third combined decoding result and the fourth combined decoding result by one of the following methods:

$S=\frac{1}{4}({\tilde{S}}^{\left(\mathrm{even}\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+{{\tilde{S}}_3}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_4}^{\left(\mathrm{combi}\right)}),$ $S=\frac{1}{3}({\tilde{S}}^{\left(\mathrm{even}\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+\frac{1}{2}({{\tilde{S}}_3}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_4}^{\left(\mathrm{combi}\right)})).$

the terminal according to the embodiment of the invention comprises: a first decoding unit for decoding a first data matrix S from the base station⁽⁰⁾And a second data matrix S^(odd)Performing space-time coding and decoding to generate a first decoding result

And a second decoding result

A second decoding unit for performing joint space-time coding and decoding on the first data matrix and the second data matrix to generate a first joint decoding result

And a second joint decoding result

And a result synthesizing unit for synthesizing the first decoding result, the second decoding result and the first linkAnd combining the combined decoding result and the second combined decoding result to generate a first combined result.

Wherein the result synthesis unit combines the first decoding result, the second decoding result, the first joint decoding result, and the second joint decoding result by one of the following methods:

$S=\frac{1}{4}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+{{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)}),$ $S=\frac{1}{3}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+\frac{1}{2}({{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)})).$

in summary, the present invention fully utilizes the diversity gain between two transmissions, so that a higher signal-to-noise ratio gain can be obtained under the condition of a slow fading channel or a quasi-static channel.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a schematic diagram of 2X2MIMO CC _ STC HARQ reception combining;

fig. 2 is a graph of 2X2MIMO CC _ STC HARQ and MIMO CC HARQ simulation performance comparison (retransmission interval of 3 ms).

Detailed Description

The main point of the present invention is to provide a data transmission method for enhancing the chase combining HARQ performance of an a matrix when the number of transmit antennas is 2, and an a matrix and a B matrix when the number of transmit antennas is 4 in the MIMO transmission at 8021.16 e.

Wherein, the retransmission mode of the transmission A matrix when the number of the transmission antennas is 2 is as follows:

the retransmission mode of the transmission A matrix when the number of the transmission antennas is 4 is as follows:

wherein, the retransmission matrix of the transmission B matrix when the number of the transmission antennas is 4 is as follows:

the HARQ combining method used in the data transmission method according to the embodiment of the present invention is as follows:

performing STC decoding on the primary transmission packet to obtain ${\tilde{S}}^{\left(0\right)}=\left[\begin{array}{c}{\tilde{S}}_1\\ {\tilde{S}}_2\end{array}\right];$

STC decoding is carried out on adjacent odd transmission packets to obtain ${\tilde{S}}^{\left(\mathrm{odd}\right)}=\left[\begin{array}{c}{\tilde{S}}_1\\ {\tilde{S}}_2\end{array}\right];$

Performing STC decoding on the corresponding column of the primary transmission packet and the corresponding column of the adjacent odd transmission packet to obtain ${{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}=\left[\begin{array}{c}{\tilde{S}}_1\\ {\tilde{S}}_2\end{array}\right];$ ${{\tilde{S}}_2}^{\left(\mathrm{combi}\right)}=\left[\begin{array}{c}{\tilde{S}}_1\\ {\tilde{S}}_2\end{array}\right];$

The results obtained above are combined by any one of the following two formulae:

$S=\frac{1}{4}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+{{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)})$

or,

$S=\frac{1}{3}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+\frac{1}{2}({{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)}))$

after the merging result is obtained, further performing subsequent processing such as demodulation and decoding.

The following describes a data transmission method according to an embodiment of the present invention, taking 2X2MIMO as an example. Wherein, fig. 1 shows a MIMO CC _ STC HARQ reception combining process. As shown in fig. 1, the process includes the steps of:

in the first step, the base station transmits the signal S at the initial transmission time₂ ⁽⁰⁾The receiving terminal feeds back the NACK request to resend and stores the decoding result of the initial sending

Second, the base station transmits S as described above₂ ^(odd)The receiving terminal carries out STC decoding after receiving to obtain

Thirdly, the receiving terminal performs joint STC decoding on the two transmissions to obtain

And

fourthly, the receiving terminal merges the obtained decoding results by the method, and further carries out demodulation and decoding processing;

fifthly, the receiving terminal feeds back the NACK request to be sent again, and stores the independent decoding result and the joint decoding result of each time;

sixthly, after receiving the NACK message, the base station sends S₂ ^(even)；

Seventh step, the receiving terminal receives S₂ ^(even)Thereafter, it is STC decoded, combined with the decoding result of the previous transmission and the adjacent two timesThe decoding results are combined as shown above, and then subsequently demodulated and decoded.

The terminal capable of implementing the above process includes: a first decoding unit for decoding a first data matrix S from the base station⁽⁰⁾And a second data matrix S^(odd)Performing space-time coding and decoding to generate a first decoding result

And a second decoding result

A second decoding unit for performing joint space-time coding and decoding on the first data matrix and the second data matrix to generate a first joint decoding result

And a second joint decoding result

And a result synthesizing unit, configured to combine the first decoding result, the second decoding result, the first joint decoding result, and the second joint decoding result to generate a first synthesized result. Wherein the result synthesis unit combines the first decoding result, the second decoding result, the first joint decoding result, and the second joint decoding result by one of the following methods: $S=\frac{1}{4}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+{{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)}),$

$S=\frac{1}{3}({\tilde{S}}^{\left(0\right)}+{\tilde{S}}^{\left(\mathrm{odd}\right)}+\frac{1}{2}({{\tilde{S}}_1}^{\left(\mathrm{combi}\right)}+{{\tilde{S}}_2}^{\left(\mathrm{combi}\right)})).$

fig. 2 is a graph of 2X2MIMO CC _ STC HARQ and MIMO CC HARQ simulation performance comparison (retransmission interval of 3 ms). Wherein the simulation is performed under SCME channel conditions. The speed of the receiving terminal is 3km/h, the modulation mode is 16QAM or QPSK, the coding mode is convolutional coding, the code rate is 1/2, the number of IFFT points is 1024, the bandwidth is 10MHz, the downlink subframe is 19 symbols, the CP length is 1/8, the whole frame is used as a retransmission unit, and the antenna configuration is 2X 2. Simulation results show that when the retransmission interval is 3ms, compared with a pure chase combining method, the method provided by the invention has at least 1dB of gain when the bit error rate is 0.01, and the throughput has 30% of increase when the signal-to-noise ratio is 0 dB. When the retransmission interval is 5ms, the method provided by the invention has at least 0.3dB gain when the error rate is 0.01 compared with a pure chase combining method, and the throughput is increased by about 2% when the throughput is 0 dB.

The present invention is designed for the ieee802.16mwimax wireless communication system, but is applicable to various orthogonal frequency division multiplexing multiple input multiple output wireless communication systems.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (6)

1. A data transmission method, comprising the steps of:

the base station sends a first data matrix S to the terminal⁽⁰⁾；

The terminal performs space-time coding and decoding on the first data matrix to generate a first decoding resultAnd sending a first retransmission request to the base station if the first decoding result is not verified;

the base station responds to the first retransmission request and sends a second data matrix S to the terminal^(odd)；

The terminal performs space-time coding and decoding on the second data matrix to generate a second decoding result

And performing joint space-time coding and decoding on the first data matrix and the second data matrix to generate a first joint decoding result

And a second joint decoding result

And

the terminal combines the first decoding result, the second decoding result, the first joint decoding result and the second joint decoding result to generate a first combined result.

2. The data transmission method according to claim 1, wherein the terminal combines the first decoding result, the second decoding result, the first joint decoding result, and the second joint decoding result by one of:

3. the data transmission method according to claim 1 or 2, further comprising the steps of:

under the condition that the first synthesis result is not verified, the terminal sends a second retransmission request to the base station;

the base station responds to the second retransmission request and sends a third data matrix S to the terminal^(even)Wherein the third data matrix is the same as the first data matrix;

the terminal performs space-time coding and decoding on the third data matrix to generate a third decoding result

And performing joint space-time coding and decoding on the second data matrix and the third data matrix to generate a third joint decoding result

And a fourth joint decoding result

The terminal combines the second decoding result, the third joint decoding result, and the fourth joint decoding result.

4. The data transmission method according to claim 3, wherein the terminal combines the second decoding result, the third joint decoding result, and the fourth joint decoding result by one of the following methods:

5. a terminal, comprising:

a first decoding unit for decoding a first data matrix S from the base station⁽⁰⁾And a second data matrix S^(odd)Performing space-time coding and decoding to generate a first decoding result

And a second decoding result

A second decoding unit, configured to perform joint space-time coding and decoding on the first data matrix and the second data matrix to generate a first joint decoding result

And a second joint decoding result

And

a result synthesizing unit, configured to combine the first decoding result, the second decoding result, the first joint decoding result, and the second joint decoding result to generate a first synthesized result.

6. The terminal of claim 5, wherein the result synthesis unit combines the first decoding result, the second decoding result, the first joint decoding result, and the second joint decoding result by one of:

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