Sequence Design Based On MUB And Research On Application In Wireless Communication

In the communication systems,sequences have very important applications.On the one hand,sequences with low correlation can be used in the Code Division Multiple Access(CDMA)communication systems to help the receivers distinguish the users accurately;On the other hand,with the development of the fifth generation of communications(5G),especially the high-speed development of Internet of Things,the system requires a very high number of connections,which puts forward a very high requirement on the capacity of the sequence set.Based on these two points,this thesis makes an in-depth study on the sequences with good correlation and the sequence set with large capacity.Firstly,focusing on multi-phase sequences,this thesis systematically summarizes the nature of a type of sequence based on Mutually Unbiased Bases(MUB)and the way to structure MUB in the context of different sequence dimensions.Secondly,this thesis further expands the structure of MUB and proposes two types of methods for constructing approximate MUB(AMUB).On the one hand,since the construction of MUB sequences requires the polynomials in finite fields,we can structure AMUB sequences by changing the structure of polynomials.On the other hand,since the precondition of constructing MUB is that the dimension of the sequence is prime or prime powers,this thesis proposes the method of raising and decreasing dimension of the sequence,so that the AMUB sequences with performance similar to MUB sequences can be constructed in any dimension.Thirdly,in order to prove the good properties of MUB sequences,we apply MUB sequences in the field of spectrum sensing,which is one of the most important technologies in cognitive radio.Based on MUB sequences and goodness of fit test,a new spectrum sensing method is proposed in this thesis.Because of the low correlation between MUB sequences,MUB can do data processing for the received sample signals,so as to expand the sample size.On this basis,MUB based the goodness of fit test is proposed.Simulation results show that when the number of received samples is limited,performance of the proposed method is improved comparing to the original test method.