TWI510035B - Demapping device and method - Google Patents

Description

Demapping device and method

The present invention relates to a demapping method, and more particularly to a demapping method for determining an optimal output based on channel conditions and input data.

Generally, the demapper (Demapper) plays the following role: after performing channel compensation on the received data, according to modulation, after each demapping process, a channel decoding of an appropriate size with a soft decision bit number is prepared. Input.

Here, after demapping, the reason why the demapper's output is not set to hard decision and soft decision is used is that the soft decision input is applied as the input of the channel decoder, and the hard decision input is applied. In theory, AWGN (Additive White Gaussian Noise) has a performance gain of 2.2dB.

However, no matter how the number of soft decision bits is increased in the demapper, the gain does not continue to increase. The number of output bits of the demapper determines the memory of the deinterleaver at the back end of the demapper in a common communication system. Body size. Therefore, when designing the demapper, attention is paid to minimizing performance degradation and reducing the number of output bits.

A well-known demapper has the following structure in order to achieve the above purpose: pre-calculate the appropriate position of the channel-compensated data, so that the number of soft decision bits is from the corresponding position. Degree output, the channel compensated data is entered as an input to the demapper based on the reference gain value of the automatic gain adjustment device located in front of the demapper.

This method is a method of determining the average level of data compensated by the channel based on the reference gain value of the automatic gain adjustment device, and good performance can be expected in the case where the channel condition is normal.

However, in the case where the channel condition becomes unpredicted, or there is interference signal such as inter-channel interference or channel interference, the input level of the demapper can be greatly changed, so if in this case, use only use The reference level of the automatic gain adjustment device determines the output of the demapper at a predetermined position, and the output of the demapper is abnormally output.

For example, when the input of the demapper enters larger than usual, most of the output of the demapper is transmitted with the output maximum value, whereas in the case where the input of the demapper enters smaller than usual, the demap is performed. Most of the output of the output is demapped to 0 and output. In this case, the performance degradation of the entire receiver cannot be avoided.

In order to reduce the performance degradation under the conditions described above, the number of output bits of the demapper should be further increased to ensure a sufficient number of bits to cope with unexpected channel conditions, but as described above, due to normal communication The system has a deinterleaver positioned behind the demapper, so the memory of the deinterleaver becomes larger according to this degree, so it is not a good solution.

Therefore, an object of the present invention to solve the above problems is to provide a reduction in the number of output bits of the demapper in order to reduce the memory size of the deinterleaver, and to minimize performance degradation. Channel status and input data are automatically determined Demap device and method for determining the optimal output.

The demapping apparatus of the present invention for solving the above-mentioned purposes is characterized by comprising: an averager that receives a compensation data and determines the degree of compensation; and a demapping function module that receives the compensation data, and And performing demapping to output a demapping compensation data; a quantizer coupled to the averaging device and the demapping function module, and quantifying the demapping compensation data according to the magnitude of the compensation and a quantization maximum value; a counter coupled to the quantizer for receiving a quantized data output by the quantizer, performing a count of the maximum value and the minimum value of the quantized data, and outputting a count result, and providing the quantized maximum value to the quantizer And a compressor coupled to the counter for compressing the counting result to reduce the number of bits.

In a preferred embodiment, the compressed result is input to a deinterleaver to reduce the memory size of the deinterleaver.

The demapping method of the present invention for solving the above objects is characterized by comprising the steps of: receiving a compensation data and determining the degree of compensation; demapping the compensation data; according to the degree of compensation and a quantization maximum And dequantizing the demapping compensation data to obtain a quantized data; counting a maximum value and a minimum value in the quantized data to obtain the quantized maximum value and a count result; and compressing the count result to reduce the bit of the count result number.

In a preferred embodiment, the count of the reduced number of bits is used to reduce the size of the memory inside a decoder.

The invention as described above has the following advantages: in an environment of various channel environments, inter-channel interference, interference interference such as channel interference, the demapping device can also automatically adapt to produce an optimal output, thereby being applied and applicable. In most communication systems.

Further, the present invention minimizes the performance degradation, reduces the number of output bits of the demapping device, reduces the memory size of the deinterleaver, or expects more excellent performance even if the same memory is used.

100‧‧‧ averager

101‧‧‧Quantifier

102‧‧‧ counter

103‧‧‧Compressor

104‧‧‧Demap function module

Fig. 1 is an overall block diagram of a demapping apparatus of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, as follows.

Fig. 1 is an overall block diagram of a demapping apparatus of the present invention.

Referring to FIG. 1, the demapping apparatus of the present invention includes, in addition to the demapping function module 104 used in the conventional demapping apparatus, an averaging device 100 for determining the degree of compensation of the received data; Quantizer 101 quantizes and outputs the result of the demapping; a counter 102 that counts the output maximum or minimum of the quantized output value; and a compressor 103 that reduces the number of bits ultimately output.

The averager 100 determines the extent of the size of the data compensated by the channel. In general, the size of the channel-compensated data varies according to the reference gain value of the automatic gain adjustment device located further ahead than the demapping device, but in the case where the channel condition is not fixed or there are multiple interference signals, the solution The input of the mapping device, ie the size of the data compensated by the channel, can vary.

In this case, the demapping device is to automatically determine the size of the input. The operation is performed in such a manner that the output is reasonably transmitted, and the quantizer of the rear is notified after the input size is calculated.

The quantizer 101 functions to calculate a quantization level suitable for the current channel condition by using information calculated according to the input and output of the demapping device, and based on the value of the quantization level, according to the output bit The number of numbers that can be divided into individual intervals determines the number of output bits produced by the input.

The counter 102 sets the maximum value of the quantizer based on the output of the quantizer, counting the number of the maximum and minimum values transmitted.

Even if the input of the demapping device, that is, the average value of the absolute values of the channel-compensated data is the same, there is a case where the output of the demapping device is excessively tilted to the maximum value or the minimum value according to the dispersion value, and therefore, according to the output of the quantizer, respectively The maximum or minimum value is counted so that the level of the quantizer is re-adjusted so that it is output at an appropriate ratio in the case where the ratio of the two values deviates from the preset appropriate ratio.

The compressor 103 functions to slightly reduce performance and reduce the number of output bits, thereby reducing the size of the memory inside the deinterleaver.

The number of samples transmitted as the output of the quantizer is determined according to the number of output bits, and the output frequencies of all the samples are different.

Here, the compressor 103 performs an operation of dividing a sample having a high specific gravity and a sample having a low specific gravity into a sample having a high specific gravity, and then replacing the sample having a low specific gravity with a specific gravity in the vicinity. High sample.

The number of final output bits can be changed according to how many the number of samples having a high specific gravity is set. Data that is replaced with a higher priority sample can also be represented in fewer bits. Therefore, it is possible to obtain a gain in which the number of output bits of the demapping device is reduced, and the size of the memory is reduced in accordance with the reduced number of bits.

After the final output bit number is reduced by this process, the action of restoring the number of bits according to the input of the channel decoder should be added. The data represented by the smaller number of bits is again restored to the output of the original demapping apparatus having the higher priority according to the input of the channel decoder.

If the data restored according to the input of the demapping device and the input of the channel decoder is compared, the values having the higher priority order are all restored to the original values, and only the data having the lower priority order is replaced by the data having the higher priority order in the vicinity. Performance degradation due to output bit reduction can be minimized.

The method of the demapping apparatus of the present invention will be described in detail below as follows.

First, if the averager 100 receives the compensation data and determines the magnitude of the compensation and notifies the quantizer 101, the quantizer quantizes the demapping compensation data and outputs a quantized data by using the degree of compensation of the data and a quantization maximum value. .

Thus, the counter 102 again determines whether the output signal has an appropriate value and notifies the quantizer 101 of the result feedback.

The quantizer 101 again utilizes the information received from the counter 102 to adjust the quantization level. This process is continuously implemented during the reception of the signal, and continues to follow the optimal output even if the channel changes.

The signal output from the counter 102 is slightly reduced in performance by the compressor 103, and the number of output bits is reduced to reduce the memory size inside the deinterleaver.

As described above, in the detailed description of the present invention, a preferred embodiment of the present invention has been described, but those having common knowledge in the technical field to which the present invention pertains should understand that Various modifications can be made without departing from the scope of the invention. Therefore, the scope of the invention should be determined according to the claims and the equivalents thereof, and not limited to the illustrated embodiments.

100‧‧‧ averager

101‧‧‧Quantifier

102‧‧‧ counter

103‧‧‧Compressor

104‧‧‧Demap function module

Claims (4)

A demapping apparatus includes: an averaging device that receives a compensation data and determines a degree of compensation; a demapping function module that receives the compensation data and performs demapping to output a demapping compensation data; And the demapping function module is coupled to the averaging device and the demapping function module to quantize the demapping compensation data according to the magnitude of the compensation and a quantization maximum value; a counter coupled to the quantizer for receiving And a quantized data output by the quantizer, in a case where a ratio of a maximum value and a minimum value is out of a preset ratio, performing counting of the maximum value and the minimum value in the quantized data and outputting a counting result, and providing the same Quantizing the maximum value to the quantizer to adjust the level of the quantizer; and a compressor coupled to the counter to compress the counting result to reduce the number of bits. The demapping apparatus according to claim 1, wherein the compressed result is input to a deinterleaver to reduce the memory size of the deinterleaver. A demapping method includes: receiving, by an averager, a compensation data and determining a degree of compensation; de-mapping the compensation data by a demapping function module; and determining, by a quantizer, the magnitude of the compensation and a quantization maximum And quantizing the demapping compensation data to obtain a quantized data; Counting a maximum value and a minimum value of the quantized data by a counter in a ratio of a maximum value and a minimum value to obtain the quantized maximum value and a count result to adjust the quantizer Level; and the result of the counting is compressed by a compressor to reduce the number of bits of the counting result. The method of claim 3, wherein the counting result of the reduced number of bits is used to reduce the size of a memory inside a deinterleaver.