CN1852046B - Detection method of physical channel energy - Google Patents

Abstract

This invention relates to a test method for the energy of a physical channel including: obtaining the maximum score of decoding based on the received information bits, then testing if there are information bits on the physical channel based on the score.

Description

Detection method of physical channel energy

technical field

The invention relates to the communication field, in particular to a method for detecting physical channel energy.

Background technique

In a wireless communication system, especially in a WCDMA (Wideband Code Division Multiple Access; Wideband Code Division Multiple Access) system, the physical channel is the carrier for information bit transmission. During the transmission process of the physical channel, when the information bits transmitted by the physical channel do not contain CRC (Cyclic Redundancy Check; Cyclic Redundancy Check) bits and special pilot bits, the receiver must be able to receive the format of which under certain circumstances is unknown signal, so the receiving end needs to perform blind detection of the signal, that is, to detect whether there are information bits to be sent on the physical channel.

The technical solution of the blind detection technology of the prior art 1 related to the present invention, as shown in Figure 1, the information bits sent by the transmitting end are sent to the receiving end by the wireless physical channel after being subjected to block coding, spectrum spreading, and scrambling. end; at the base station side of the receiving end, first descramble and despread the received signal to obtain M information bit values, which correspond to the Mbit before spreading at the transmitting end; then, calculate the energy for each bit (information bit), and use M These energies are accumulated, and then the accumulated sum is compared with a preset threshold T (T can be determined by a certain false alarm probability index, for example, T must satisfy a 1% false alarm probability), and if it is greater than this threshold, the physical channel is considered If there is information bit transmission on the physical channel, otherwise, it is considered that there is no information bit transmission on the physical channel.

It can be seen from the technical solution of the prior art that it calculates the energy for each bit (information bit), and then accumulates the M energies and compares them with the preset threshold, without utilizing the correlation between the M bits , so the system cannot achieve better performance.

The technical solution of the blind detection technology of the second prior art related to the present invention, as shown in Figure 2, the information bits sent by the transmitting end are sent to the receiver by the wireless physical channel after block coding, frequency spreading, and scrambling. end; at the base station side of the receiving end, firstly descramble and despread the received signal to obtain M values corresponding to the Mbit before spreading at the transmitting end; at the same time, another demodulation branch performs descrambling, despreading, deviation correction, Decoding to obtain the first N information source bits; then perform the same (M, N) block encoding as the transmitter to obtain the encoded Mbit; then perform point multiplication between this Mbit and the despread M values, After dot multiplication, perform M/3 times of coherent accumulation to obtain M/3 times of coherent accumulation results; then calculate the energy of the M/3 times of coherent accumulation results, and then perform 3 non-coherent accumulations; finally, combine the accumulated sum with a preset Threshold T (T can be determined by a certain false alarm probability index, such as T to meet the false alarm probability of 1%.) comparison, greater than this threshold, it is considered that there is information bit transmission on the physical channel, otherwise, it is considered that there is no information bit in the physical channel sent on the physical channel.

Since the wireless channel is a fading channel, it fades according to a certain period and performs phase inversion. For M bits, its phase may be completely opposite. At this time, the effect of coherent addition is negative; and M/3 The corresponding bit phases in the sub-coherent cycle are generally in-phase, so the performance of the system is far better than the prior art 1 after M/3 times of non-coherent accumulation is adopted instead of M times of coherent accumulation in prior art 2. However, the structure of the technical solution of the prior art 2 is relatively complicated, and this method only calculates the energy of the M/3 coherent accumulation results, and then performs 3 non-coherent accumulations, and finally combines the accumulated sum with a preset threshold T is compared to detect the energy on the physical channel, but it still does not make full use of the correlation between Mbits, so it cannot obtain a better performance effect of the communication system.

Contents of the invention

In view of the problems existing in the above-mentioned prior art, the object of the present invention is to provide a method for detecting physical channel energy, by which the correlation between M information bits can be fully utilized, thereby obtaining a method that is better than the prior art. system performance; moreover, the technical structure of the present invention is relatively simple, so it has good realizability.

The purpose of the present invention is achieved through the following technical solutions:

A method for detecting physical channel energy provided by the present invention includes:

A. On the base station side, obtain the maximum decoding scoring value according to the received information bits;

B. Detect whether information bits exist on the physical channel based on the maximum decoding score value.

Wherein, the step A specifically includes:

A1. On the base station side, descramble and despread the received information bits successively;

A2, correcting the processed information bits to obtain some despreading values in the same codeword matrix when the corresponding block is encoded;

A3. Do point multiplication of some despread values obtained after deviation correction with each of several dimension vectors in the code word matrix, and accumulate the result of the point multiplication to obtain the value corresponding to each row vector in the corresponding code word matrix Decoding scoring value;

A4. Compare the decoding scoring values, and select the maximum decoding scoring value.

Wherein, the step B specifically includes:

B1. Comparing the maximum decoding score value with the set threshold, when the maximum decoding score value is greater than the threshold, confirm that there is information bit transmission on the physical channel; otherwise, confirm that there is no information bit on the physical channel Information bits are sent.

Wherein, the step B specifically includes:

B2. Squaring the maximum decoding scoring value to obtain the square value of the maximum decoding scoring value;

B3. Comparing the square value with a set threshold, when the square value is greater than the threshold, confirm that there is information bit transmission on the physical channel; otherwise, consider that there is no information bit transmission on the physical channel.

Wherein, the set threshold is determined by a false alarm probability index.

Among them, before performing step A, it also includes:

C1. At the transmitter, block-encode the information bits transmitted on the physical channel;

C2. Perform spectrum spreading and scrambling successively on the encoded information bits of the block, and transmit the processed information bits to the base station at the receiving end via a wireless channel.

Wherein, the code word corresponding to the maximum decoding score value is an information bit obtained after encoding the source information bit sent by the transmitting end; the index of the code word corresponds to the source information bit sent by the transmitting end.

It can be seen from the above-mentioned technical solution provided by the present invention that the present invention first descrambles, despreads, corrects and decodes the received signal on the base station side to obtain the maximum decoding score value; then based on the maximum decoding score Value detection of information bits on the physical channel, the technical solution based on the maximum scoring value of the present invention can make full use of the correlation between M information bits, so as to obtain better system performance than the prior art; moreover, the present invention The technical structure is relatively simple, so it has good realizability.

Description of drawings

Fig. 1 is the flowchart of prior art one;

Fig. 2 is the flow chart of prior art 2;

Fig. 3 is a flowchart of the present invention;

Fig. 4 is a system performance curve obtained by applying the present invention and a system performance curve obtained by applying the prior art.

Detailed ways

The present invention provides a physical channel energy detection method, the core of which is: firstly, at the base station side, after descrambling, despreading, deviation correction and decoding of the received signal, the maximum decoding scoring value is obtained; then based on the maximum The decoding score value detects information bits on the physical channel.

Embodiment provided by the present invention, as shown in Figure 3:

At the transmitting end, the implementation steps are the same as those of the existing technology, mainly including:

Firstly, the information bits transmitted by the physical channel are subjected to code word matrix block encoding processing to obtain block-encoded information bits; then the encoded information bits are subjected to spreading and scrambling processing; and then transmitted to the receiving end through the wireless physical channel base station side.

On the base station side of the receiving end, the processing of the received information bits includes:

Step 1, descrambling and despreading the received information bits successively;

Step 2, performing deviation correction processing on the processed information bits to obtain some despreading values in the same codeword matrix during encoding of the corresponding block;

Step 3, do point multiplication with several despread values obtained after deviation correction and each several-dimensional vector in the code word matrix in turn, and accumulate the result of the point multiplication to obtain each vector in the corresponding code word matrix Corresponding decoding scoring value;

Step 4: Comparing the decoding scoring values and selecting the maximum decoding scoring value.

Step 5: Detect the physical channel based on the maximum decoding score value.

Wherein, the process of detecting the physical channel based on the maximum decoding score value includes two cases, of which only the second case is shown in FIG. 3 .

In the first case, the maximum decoding scoring value is directly compared with the set threshold, and when the scoring value is greater than the threshold, it is confirmed that there is information bit transmission on the physical channel; otherwise, it is confirmed that there is no information bit on the physical channel. Information bits are sent.

The second case includes:

Step 1. Square the maximum decoding scoring value to obtain the square value of the maximum decoding scoring value;

Step 2: Comparing the square value with a set threshold, when the square value is greater than the threshold, it is confirmed that there is information bit transmission on the physical channel; otherwise, it is considered that there is no information bit transmission on the physical channel.

Wherein, the set threshold is determined by a certain false alarm probability index. For example, T must meet the false alarm probability of 1%.

The following uses the transmission of Nbit information bits on the physical channel as an example to illustrate the specific implementation process of detecting the physical channel on the base station side in the above embodiment:

At the transmitting end, the information bits of Nbit are sent on the physical channel, and at first the information bits of the Nbit are block coded with M=30, N=10 codeword matrix (M columns in total; 2 ^N rows), because in In the codeword matrix, each row corresponds to a vector, so 30-bit information bits can be obtained after block encoding; then the encoded information bits are spread and scrambled, and the processed information bits are transmitted to the receiving end base station side.

On the base station side, descrambling and despreading are first performed on the received information bits, and then deviation correction is performed on the processed information bits to obtain M=30 despreading values, corresponding to 30 bits after block encoding; The processed information bits are decoded, that is, the 30-dimensional despreading result is dot-multiplied by each 30-dimensional vector in the 1024×30 code word matrix, and then accumulated to obtain 1024 accumulated sums, each accumulated result is a Decode the scoring value. Then compare these decoding scoring values to obtain the maximum decoding scoring value, the codeword corresponding to the maximum decoding scoring value is the information bit obtained after encoding the source information bits sent by the transmitting end; the index of the codeword corresponds to the transmitting The source information bits sent by the terminal. For example, the corresponding codeword is 30 bits obtained after block encoding, and the codeword index, such as any line in block encoding 2 ^N lines, the 10 bits corresponding to the line number are the transmitted information source bits, and also correspond to the decoding output in Figure 3 After the information bits.

It can be seen from the above-mentioned technical solution of the present invention that the present invention can make full use of the correlation between encoded information bits, thereby obtaining optimal system performance. As shown in Figure 4, according to the same set threshold, taking N=10, M=30, and spreading factor SF=256 as an example, the system performance obtained by adopting the technical solution of the prior art 1 is shown in curve 1. The system performance obtained by the technical solution of prior art 2 is shown in curve 2, and the system performance obtained by adopting the technical solution of the present invention is shown in curve 3, so the present invention can obtain better system performance than the prior art.

In addition, the technical structure of the present invention is relatively simple, so it has good realizability.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (6)

1. the detection method of a physical channel energy is characterized in that, comprising:

A, in base station side, obtain maximum decoding marking value according to the information bit that receives, described steps A specifically comprises:

A1, in base station side, the information bit that receives is successively carried out descrambling and despreading handles;

The processing of rectifying a deviation of A2, the information bit after will handling, the some despread values when obtaining the corresponding blocks coding in the same code word matrix;

Some despread values that A3, the back of will rectifying a deviation obtain and each the some dimensional vector in the described code word matrix are made dot product, and described dot product result is added up, and obtain the decoding marking value of each the row vector correspondence in the corresponding code word matrix;

A4, more described decoding marking value are chosen maximum decoding marking value;

B, detect on the physical channel whether have information bit based on described maximum decoding marking value.

2. method according to claim 1 is characterized in that, described step B specifically comprises:

B1, described maximum decoding marking value is compared with setting thresholding,, then confirm to exist on this physical channel information bit to send when described maximum decoding marking value during greater than described thresholding; Otherwise, confirm not have on this physical channel information bit to send.

3. method according to claim 1 is characterized in that, described step B specifically comprises:

B2, described maximum decoding marking value is carried out square, obtain the square value of described maximum decoding marking value;

B3, described square value is compared with setting thresholding,, then confirm to exist on this physical channel information bit to send when described square value during greater than described thresholding; Otherwise thinking does not have the information bit transmission on this physical channel.

4. according to claim 2 or 3 described methods, it is characterized in that described setting thresholding is determined by false alarm probability indicator.

5. method according to claim 4 is characterized in that, before execution in step A, also comprises:

C1, at transmitting terminal, the information bit that will transmit on physical channel carries out block encoding;

C2, the information bit behind the described block encoding is successively carried out spread spectrum and scrambling handle, and the information bit after will handling sends the base station of receiving terminal to through wireless channel.

6. method according to claim 1 is characterized in that, the code word of described maximum decoding marking value correspondence is the information bit that obtains after the source information bits of encoded of transmitting terminal transmission; The source information bit that the corresponding transmitting terminal of the index of described code word sends.

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