Summary of the invention:
The purpose of this invention is to provide a kind of radio communication Space-Time Block Coding building method, can construct the Space-Time Block Coding that is applicable to the mimo system that is equipped with six or eight transmitting antennas, four reception antennas according to the inventive method, this sign indicating number has fast operation, overhead is low, characteristics such as function admirable.
The invention provides a kind of building method of Space-Time Block Coding, it is characterized in that adopting following encoder matrix constitution step: step 1: construct a real orthogonal matrix the simplest:
The signaling channel symbol is x
1(x
1For greater than 0 real number), x
2(x
2Be real number), the channel symbol cycle is T, and they are carried out Space Time Coding, sends with two antennas according to following mode:
| |
Antenna 1 |
Antenna 2 |
| Time t t+T |
x
1-x
2 |
x
2x
1 |
Top coded system can be used matrix:
Expression, it is an orthogonal matrix;
Step 2: increase transmitting antenna, make it to reach 8 antennas.Corresponding to the dimension (columns that is it is 8) that increases matrix in the step 1, just every transmit antennas is corresponding to row of encoder matrix, and we can expand to 8 * 8 orthogonal matrix to it by mending 0 method, mends 0 result to be:
Top matrix notation is sent out two real channel symbol x with 8 antennas, 8 time slots
1, x
2
Step 3:, increase the real channel symbol x of transmission in order to transmit more information
3, x
4, corresponding on the encoder matrix of step 2 gained, increasing real symbol x
3, x
4, promptly the corresponding 0 position real symbol x that mends in the matrix
3, x
4Replace, the orthogonal coding matrix after can obtaining substituting is as follows:
Above matrix notation with 8 antennas, 8 time slots are sent out four real channel symbol x
1, x
2, x
3, x
4Step 4: further increase transmission information, increase channel real symbol x
5And x
6, corresponding on the encoder matrix of step 3 gained, increasing real symbol x
5And x
6, corresponding 0 position x in the matrix
5And x
6Replace, it is as follows to obtain substituting back orthogonal coding matrix:
Above matrix notation with 8 antennas, 8 time slots are sent out six real channel symbol x
1, x
2, x
3, x
4, x
5, x
6Step 5: last, we need transmit 8 real channel symbol x
1, x
2, x
3, x
4, x
5, x
6, x
7, x
8, increase the real channel symbol x of transmission
7And x
8, corresponding to increasing real symbol x on the gained matrix in the step 4
7And x
8, corresponding 0 position x in the matrix
7And x
8Replace, it is as follows to obtain final orthogonal coding matrix X:
Above matrix notation with 8 antennas, 8 time slots are sent out eight real channel symbol x
1, x
2, x
3, x
4, x
5, x
6, x
7, x
8Step 6: the multiple encoder matrix of the pairing generalized orthogonal of real orthogonal coding matrix X that constitution step 5 obtains:
In practice, channel symbol generally all has plural form, and therefore, we are necessary to introduce the plural form of real orthogonal matrix X.Can carry out following processing (makes plural number with all elements of matrix here and considers, be i.e. x
i=Re (x
i)+j Im (x
i), i=1,2 ..., 8, wherein,
Here Re (x) is meant the real part of getting x, and Im (x) is meant the imaginary part of getting x.
We have obtained real orthogonal coding matrix X the front, equally we use the same method (repeating step 1~5) obtain another real orthogonal coding matrix X ':
X wherein
1' be real number greater than 0, x
2', x
3', x
4', x
5', x
6', x
7', x
8' be real number.
Then, the Generalized Complex Variable orthogonal matrix S of structure real matrix X correspondence
8:
Complex matrix S
8Have following character:
Wherein, the conjugate transpose of subscript " H " representing matrix, I
8The unit square formation on one 8 rank of expression, ρ represents a constant, the size of ρ is:
This shows S
8It is a broad sense complex orthogonal matrix.
S wherein
1, s
2... s
8Be the complex channel symbol, and s
i=x
i+ jx
i' i=1,2...8.
Top matrix notation is with 8 antennas, by 8 complex channel symbol sx of 16 time slots emissions, s
2... s
8
Broad sense complex orthogonal matrix S
8Be and comprise that 8 transmit antennas, 4 reception antennas (are called for short: the Space-Time Block Coding of mimo system 8 * 4);
In like manner, the Space-Time Block Coding method of the mimo system of structure 6 * 4 (i.e. 6 transmit antennas, 4 reception antennas) is S
8The two row deletions of matrix back just can obtain 6 * 4 encoder matrix S
6:
Top matrix notation is launched 8 complex channel symbol s with 6 antennas by 16 time slots
1, s
2... s
8
Through after the above-mentioned steps, just can construct the Space-Time Block Coding of the mimo system that is applicable to six of outfits or eight transmitting antennas, four reception antennas.
Innovation part of the present invention is:
Compare with (2 * 2) Space-Time Block Coding that existing Alamouti proposes, the present invention is by the quadrature spread to encoder matrix, according to the Hurwitz-Radon theory, increase number of transmit antennas, constructed a kind of Space-Time Block Coding of high-order antenna number, promptly adopted the high-order antenna number to realize for the full-diversity on the mimo system, it has better system performance than more previously presented Space-Time Block Codings, channel capacity that within the specific limits can elevator system, and can improve communication quality.
(8 * 4) Space-Time Block Coding that uses method construct of the present invention is to be 8 transmit antennas, the space-time coding method of the mimo system design of 4 reception antennas, and it also is applicable to 8 transmit antennas, the situation of n root reception antenna; Equally, be to be 6 transmit antennas with the Space-Time Block Coding of (6 * 4) of this method construct, the mimo system design of 4 reception antennas, it also is applicable to 6 transmit antennas, the situation of n root reception antenna.
Advantage of the present invention:
The present invention has constructed the Space-Time Block Coding scheme of a kind of (8 * 4) and (6 * 4), and it is compared to previously presented Space-Time Block Coding following advantage:
1). this scheme is within the specific limits, communication quality and efficient under the wireless multi-path environment have effectively been improved, here the connotation of " certain limit " is meant: owing to be subject to the mimo channel capacity, antenna number is not unrestrictedly to increase, and is very little performance boost because the sharp increase of system handles operand brings.Can find out in the performance comparison diagram among Fig. 4 from Fig. 3;
2) though. because the complex signal of high-order mapping can more effectively be utilized signal space, but too small Euclidean distance will cause the serious reduction of radio communication decoding quality between signaling point, this scheme has been carried out compromise to this problem and has been considered, adopt suitable modulation scheme, guaranteed systematic function, adopt the different resulting performance curves of modulation system to make analysis to different empty time-codes among Fig. 4, can select the scheme that a kind of best empty time-code adds modulation system;
3). under identical modulation system, the performance of the Space-Time Block Coding of (8 * 4) is better than the performance of the Space-Time Block Coding of (6 * 4), as can be seen from Figure 3;
4). the present invention has effectively promoted radio communication quality and can guarantee suitable treatment effeciency.