Although radio access technology has huge expansion in the past decades, interference management is a key concern for today’s mobile communication systems, a concern in the demand by an ever increasing range of potential applications.
Future wireless network including LTE-advanced(also known as the standard for the next generation mobile communication system) will not only need to support higher data rate comparing with existing mobile network in order to meet the increasing customer demand for multimedia services, but also new techniques are under research to decrease high interference comparing with current LTE system.
Relay nodes are supposed to be supported in LTE-advanced, which will bring a huge technical innovation for current network’s structure. Network coding in relay network application is already proved to increase the throughput, improve system’s efficiency and enhance system capacity in many papers. Together with relay nodes, the new standard will also make some deep research in interference management, for example evolved inter-cell interference coordination(eICIC)
and coding schemes.
This study focuses on the performance acquired in multiple access relay channel(MARC) together with network coding technique, on the other hand, a new channel coding method, namely nested lattice coding, has attracts most of interests throughout this master thesis.
In this MARC network, the sources map their messages using lattice code and then broadcast them to the relay and the destination. The relay receives two independent symbols through the same channel, it will combine the two symbols using modulo lattice and then forward the new symbol to the destination node.
The destination recovers those two messages using two linear equations one directly from the sources and the other one forwarded by the relay. Although this method will have some information loss, while it reduces the transmission time slots and improves the system’s efficiency.
The implementation of nested lattice in MARC network also introduces modulo lattice transformation to achieve the capacity, where the coarse lattice is used for shaping while the fine lattice serving for channel coding. It is proved that for the modulo-lattice additive noise channel, lattice decoding is optimal.
Source: KTH
Author: Wen, Qiang