Improvement of processing time using residue number system and sorting network in controller design

This paper presents and proposes two approaches to speed up for the controller unit. One is a residue number system (RNS), the other is a sorting network. Using an RNS reduces the total bit size of adder and carry-propagation delays. Also, using sorting network makes comparing time of 16 input data sequences within 10 clocks. First, this paper introduces the basic concept of an RNS and a sorting network. Next, we design the controller using the RNS adder and Green model 16-input sorting network. We present experimental results about elevator group control by applying these two approaches. Experimental results show that the RNS can reduce adder size, which calculates an elevator attractive function (EAF) value, to 5-bit and its carry propagation delay within a single residue. The results also demonstrate that a sorting network is able to choose the best elevator to serve against passenger's request by comparing the attractive function value of each elevator with in 4 clocks. It means that our primary goal can be achieved by these two approaches.