Access Request of IDMA using Slotted ALOHA and PLNC
Date Issued
2015
Date
2015
Author(s)
Yeh, I-Hsien
Abstract
Interleave Division Multiple Access (IDMA) is a type of multiple access communication techniques. In IDMA system, user specific interleavers are employed to separate from on user to another. It has been shown that IDMA can provide high spectral efficiency. Physical Layer Network Coding (PLNC) is originally used in a physical-layer network coded two-way relay system. It can help increase transmission throughput. In this thesis, we will combine IDMA and PLNC techniques to deal with the collision problems on random access request stage. We thoroughly introduce IDMA system and PLNC system separately. In respect of IDMA, we will discuss about real channel and complex channel scenarios. Secondly, we analyse and implement PLNC with different modulations including BPSK and QPSK modulations. We consider that the above two techniques will help in respect of access request in IDMA slotted Aloha. When the users in IDMA system choose the same interleaver, we call this situation as collision in this thesis. In collision situation, the packets of original IDMA users who access to the same interleaver will be discarded and obey exponential back off algorithm for retransmission. Originally, IDMA receiver may not decode the non-collision packets correctly without increasing spreading length. In order to enhance the successful rate in collision situation of multiple access system''s, we perform PLNC techniques to decode the collision packets. It can not only maintain the data rate but also, with high probability, decode the collision packets. Finally, we extend the IDMA principle in resect of channel estimation in IDMA systems.
Subjects
Interleave division multiple Access
physical layer network coding
random access
channel estimation
Type
thesis