Joint detection and decoding for polar-coded IDMA-MIMO systems

Abstract

The demand on data traffic and bandwidth requirements have continued to grow exponen- tially. Nevertheless, existing fourth generation (4G) networks are not capable of meeting those demands for high data rates and bandwidth requirements. Therefore, the fifth genera- tion (5G) wireless access technology, which guarantees highzspectralzefficiency, lowzlatency,z andzmassivezconnectivity, was recently introduced. Non orthogonal multiple access (NOMA), which enables massive connectivity, was one of the key potential physical-layer technologies considered for 5G. Interleave division multiple access (IDMA) scheme iszonezofzthe promis- ing NOMAzschemes, with packet level interleavers to distinguish multiple access users. On the other hand, recently, polar codes have received increased attention as a capacity ap- proaching code. Polarzcodeszhave alreadyzbeen adopted aszthe channelzcodingztechniquez forz the physical-layer control channel of 5G New Radio (NR) networks. In the litera- ture, to date, there is only limited research on polar-coded IDMAzsystems. Multiple-Input Multiple Output (MIMO) enables thezspatial degrees of freedom through use of multi- plezantennaszatzbothz theztransmitterzandz thezreceiver.zMIMO has been one ofzthe key enabling technologieszin recent standardized wireless communication systems including 3G HSPA and 4G LTE systems. The performance benefits of both IDMA and MIMO can be obtained by combining two technologies. To this end, in this research study, an extension of conventional polar-coded IDMA to MIMO is considered for uplink communication. A polar-coded IDMA-MIMO uplink system model with QPSK modulation is proposed. An iterative receiver scheme is devised for polar- coded IDMA-MIMO systems. Inzthezproposedzreceiver, likelihoodzmessageszarezexchanged inzeachziteration betweenzthezsoftzmultiuserzMIMOzdetector and beliefzxpropagation (BP)z algorithm-basedzdecoder. The error performancezofzthezproposed system is investigated us- ing simulation for different system configurations. The simulation results confirm that polar coding offers significant performance improvement over the uncoded IDMA-MIMO system. Moreover, considerably improved error performance can be obtained by using the proposed iterative receiver scheme over single-pass multiuser MIMO detection and decoding. Further, higher the signal to noise ratio, the faster the convergence rate is.