Evaluation of Age of Information for LDPC Coded Transmission over AWGN Channels
Mangang Xie, Qianfan Wang, Jie Gong, Xiao Ma · 2019
Age of information (AoI) is an important metric in real-time status update communication system to assess the freshness of information. Different from previous works, this paper focuses on the average AoI over additive white Gaussian noise (AWGN) channels. A fixed redundancy (FR) coding scheme is considered, which encodes each k-bits update as an n-bits packet by a low-density parity-check (LDPC) code. By using the renewal-reward theory, a closed-form expression of the average AoI under the FR scheme is derived. Simulation results show that the average AoI relies on Eb/N0, especially in the low Eb/N0region. For different Eb/N0, an optimal code length always exists to minimize the average AoI. In addition, the same average AoI can be achieved with different code lengths in the high Eb/N0region. Hence, in the high Eb/N0region, short codes are preferred especially when the transmission delay is taken into account.