Jump code transmission method in sparse code multiple access based on time-varying codebook

Abstract

The invention provides a jump code transmission method in sparse code multiple access based on a time-varying codebook, which belongs to the technical field of non-orthogonal multiple access. The method comprises the steps that when each user registers a network, the user ID, a fixedly used pilot sequence and a jump code sequence pointed by the pilot sequence are assigned; when the user carries out data transmission, the pre-assigned pilot sequence is first sent; the user codes and groups data information to be transmitted to acquire SCMA blocks; the SCMA blocks are transmitted according to the codebook appointed by the jump code sequence; a receiver decodes the pilot sequence, identifies the access user and acquires the collision of the codebook; a decoder decodes each SCMA block according to the decoding complexity threshold established by the receiver to acquire the log likelihood ratio of the SCMA block; and each access user ID and the corresponding transmission data information are finally acquired. According to the invention, the SCMA transmission accuracy is improved; the decoding complexity is reduced through additional accuracy compromise; and delay is reduced.

Description

technical field [0001] The invention relates to the technical field of non-orthogonal multiple access, in particular to a code-hopping transmission method in sparse code multiple access based on a time-varying codebook. Background technique [0002] Sparse Code Multiple Access SCMA (Sparse Code Multiple Access) allocates codebooks for users to implement non-orthogonal multiple access. Through the sparsity design of the codebook, it can be ensured that the receiver can still decode when the codewords from multiple different codebooks are superimposed together, so as to realize the overload when the number of access users is more than the number of available orthogonal communication resources, and increase the Connectable number, which cannot be realized by traditional orthogonal multiple access. It is precisely because of this feature that SCMA does not require users to establish a connection with the base station in advance for transmission, but allows users to directly acc...

AI Technical Summary

Problems solved by technology

The biggest problem with this solution is that although SCMA can provide a certain number of different codebooks, it is impossible to pre-allocate each user to a different codebook

However, when there is a serious codebook conflict and multiple users use the same codebook, it will lead to extremely high decoding complexity, and the corresponding increase in decoding time may eventually destroy the real-time requirements for low-latency access.

Moreover, such high-complexity decoding often means a high symbol error rate

The receiver probably took a long time to decode and only got the wrong result

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