The communications of Mobile Cognitive Radio Base Station (MCRBS) can be extended, e.g., by using Unmanned Aerial Vehicles (UAVs). The communications between MCRBS and UAV are expected to work efficiently in dynamic channels. This thesis proposes Semi-Rateless Accumulate Tornado codes for UAV communications assisting disaster’s victims to communicate through MCRBS to ask for help.
Quasi-cyclic low-density parity check (QC-LDPC) codes is considered in this thesis based on the fifth telecommunication generation (5G) new radio (NR) as the channel coding for the UAV communications. Based on Raptor coding principle, this thesis designs Semi-Rateless Accumulate Tornado codes by extending 5G NR QC-LDPC codes to utilize accumulators. This thesis also provides girth-4 elimination after the extension codes of accumulator to make better performance because intersecting extrinsic information transfer (EXIT) curves at low value of log-likelihood ratio (LLR) can be avoided. This thesis evaluates the proposed Semi-Rateless Accumulate Tornado codes using a series of computer simulations.
The proposed Semi-Rateless Accumulate Tornado codes for UAV communications in disaster recovery networks are evaluated in terms of bit-error-rate (BER) and frame-error-rate (FER) under additive white Gaussian noise (AWGN) and the proposed UAV channels followed by EXIT chart analysis of the decoding behaviour. The simulation results confirmed that the proposed codes have about 3 dB better BER and FER performances compared to that of 5G NR QC-LDPC codes under the AWGN and UAV channels. EXIT chart of the proposed codes shows that accumulator help the QC-LDPC codes reaches (1,1) point of mutual information without an intersection. This improvement is coming from the fact that degree-1 of check nodes is no longer existing with the help of the accumulator.