Design and Analysis of Inter-RBs Hopping SCMA System under Jamming Attacks

Sparse code division multiple access (SCMA) technology has superior time-frequency resource utilization, which can support a large-scale connectivity in B5G/6G cellular. However, the prototypical SCMA always transmits the non-zero code-words over the fixed resource-blocks (RBs), thus likely suffering from severe performance degradation due to the external jamming threats. To address this issue, an improved SCMA system based on inter-RBs hopping is proposed in this paper, where physical RBs utilized by codewords are randomly hopped over the RB-group (i.e., frequency-hopped (FH) subcarriers). To implement the optimal inter-RB hopping SCMA, a pseudo-random hopping strategy is designed via prime code and interleavering operations. By such a hopping strategy, the instantaneous RB of SCMA is uniformly operated over the whole RB-group. Followed by the transceiver of proposed inter-RB hopping SCMA, the signal processing is derived in details. The signal processing and simulation results show that, under the jamming scenarios, the proposed inter-RB hopping SCMA system can reduce/average the effect of jamming on bit-error-rate performance, compared to the traditional SCMA systems.