If the voice signal is modulated and sent directly after channel coding, because the state becomes the wireless communication channel, deep fading affects consecutive bit sequence and causes a high bit error rate.
If the bits of consecutive string of addresses, or lost, the other end of the communication can not be disassembled disturbed or lost bits. To solve this problem, some technique or method to distinguish a sequence of bits are required. Thus, successive bits of the message can be sent to a decentralized manner so that the bit error should be separate. In this manner, even if errors, the errors are only one or a very short bit stream which is not followed, that the onset of full or the complete message can not be decoded block. In this case, the channel coding comes into force, and back to a few mistakes. This method is called interlacing tekniikkaa.Lomituksen method is the most effective method of encoding the dispersion few errors.
The most important thing is to break down some of the interleaving bits (I guess is the "b" bits) to a code (suppose to be "the" bursts), burst sequences in such a way to change the relationship between adjacent bits. The higher the value of "n" is, the better is the transmitting works. However, the transmission delay is greater too. Therefore, the balance of the required relief to be associated with the channel. In the GSM system, a second interleaving is applied.
After channel coding, the extracted bits 456 are divided into eight groups, with each group having 57 bits. This is the first interleaving, also called the internal interleaving, as shown in the above diagram. Through the first interleaving successive groups of messages are scattered. One of the burst position in two segments of speech information consists of 57 bits. It is clear that if two groups of 57 bits of information about the interleaving of the first consecutive 20 ms speech blocks are arranged in the same sequence burst, burst loss leads to a loss of 25% of the bits 20 ms speech block. And therefore, requires a two-tone interleaving blocks, called the inter-block interleaving or other interleaving.
Let us assume that the audio section B is divided into eight categories: inter-block interleaving performed in the first four groups (B0, B1, B2, and B3), block B, and the last four groups (A4, A5, A6 and A7) to the previous audio block, so four bursts consist of: (B0, A4), (B1, A5), (B2, A6) and (B3, A7) to break the adjacency relationship between successive bits, the bits in the block to occupy the position even if the burst, when the bits of the block B to occupy a strange position to explode. For example, B0 takes a little odd to explode when A4 takes even a little bit. Similarly, to perform interleaving block of the last four groups B and the first four groups of the next block C. The second interleaving 20 ms speech block is inserted into the eight sequences of different bursts, respectively, and then sent one at a time. Although the size of the burst is lost during the transmission process, only 12.5% of each block affects the sound, and errors can be corrected by channel at the other end. In addition, the second de-interleaving for controlling the various asia.Lomittelutila is (B0, B4), (B1, B5), (B2, B6) and (B3, B7).
If the bits of consecutive string of addresses, or lost, the other end of the communication can not be disassembled disturbed or lost bits. To solve this problem, some technique or method to distinguish a sequence of bits are required. Thus, successive bits of the message can be sent to a decentralized manner so that the bit error should be separate. In this manner, even if errors, the errors are only one or a very short bit stream which is not followed, that the onset of full or the complete message can not be decoded block. In this case, the channel coding comes into force, and back to a few mistakes. This method is called interlacing tekniikkaa.Lomituksen method is the most effective method of encoding the dispersion few errors.
The most important thing is to break down some of the interleaving bits (I guess is the "b" bits) to a code (suppose to be "the" bursts), burst sequences in such a way to change the relationship between adjacent bits. The higher the value of "n" is, the better is the transmitting works. However, the transmission delay is greater too. Therefore, the balance of the required relief to be associated with the channel. In the GSM system, a second interleaving is applied.
After channel coding, the extracted bits 456 are divided into eight groups, with each group having 57 bits. This is the first interleaving, also called the internal interleaving, as shown in the above diagram. Through the first interleaving successive groups of messages are scattered. One of the burst position in two segments of speech information consists of 57 bits. It is clear that if two groups of 57 bits of information about the interleaving of the first consecutive 20 ms speech blocks are arranged in the same sequence burst, burst loss leads to a loss of 25% of the bits 20 ms speech block. And therefore, requires a two-tone interleaving blocks, called the inter-block interleaving or other interleaving.
Let us assume that the audio section B is divided into eight categories: inter-block interleaving performed in the first four groups (B0, B1, B2, and B3), block B, and the last four groups (A4, A5, A6 and A7) to the previous audio block, so four bursts consist of: (B0, A4), (B1, A5), (B2, A6) and (B3, A7) to break the adjacency relationship between successive bits, the bits in the block to occupy the position even if the burst, when the bits of the block B to occupy a strange position to explode. For example, B0 takes a little odd to explode when A4 takes even a little bit. Similarly, to perform interleaving block of the last four groups B and the first four groups of the next block C. The second interleaving 20 ms speech block is inserted into the eight sequences of different bursts, respectively, and then sent one at a time. Although the size of the burst is lost during the transmission process, only 12.5% of each block affects the sound, and errors can be corrected by channel at the other end. In addition, the second de-interleaving for controlling the various asia.Lomittelutila is (B0, B4), (B1, B5), (B2, B6) and (B3, B7).
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