Grouping Length Permutation Encapsulated Packets to Improve Spectral Efficiency

This letter proposes a novel transport-layer encapsulation scheme, which integrates the permutation-based transmission and the packet grouping to improve spectral efficiency. For a group of packets, each data unit (DU) is divided into three portions: permutation-conveyed DU (PCDU), grouping-conveyed DU (GCDU), and conventionally conveyed DU (CCDU). The PCDU is conveyed through the selection among various lengths for GCDU plus CCDU. The GCDU is used for forming sub-groups so that, in each sub-group, the GCDU is encapsulated into the first packet only while removed from the other packets. Unlike CCDUs, the delivery of PCDUs and removed GCDUs does not consume any communication resource. To promote the improvement of spectral efficiency, an algorithm based on the binary search tree is proposed for the GCDU design in each sub-group, and a lower bound on the number of bits in the removed GCDUs is achieved in closed-form. Illustrative numerical results substantiate the spectral efficiency gain obtained by our permutation-based scheme in comparison with the conventional transport-layer encapsulation.