Suriya, A. September 19, 2015, Slide 0 Atipong Suriya School of MIME March 16, 2011 FE 640 : Term Project Presentation RFID Network Planning using Particle Swarm Optimization (PSO)

Suriya, A. September 19, 2015, Slide 1 Outline Introduction Problem Description Problem Solution Results and Discussions Conclusions

Suriya, A. September 19, 2015, Slide 2 Introduction Fig 1. An infrastructure of typical RFID System ( Benefits: o Not require line of sight (Non-LOS) o Multiple tag can be read in one time, o Reduce time and operators in processing, o Can be used for tracking of physical objects in real time such as inventory and asset tracking. The benefits of RFID in term of inventory monitoring and tracking can improve the performance of inventory management system in the warehouse. -> Focus on the placement of RFID readers in warehouse. Barcode RFID

Suriya, A. September 19, 2015, Slide 3 Problem Description Problem Statement RFID readers are expensive. The effective placement of RFID readers in the warehouse is needed. (high implementation cost) Currently, the placement of RFID readers are based on trial and error basis; therefore, the automated tool is required. (trial and error) With the trial and error method, it often results in less than optimal signal coverage and high level of interference. This directly affect the reliability of RFID system in term of reader-tag communication and tag reading. (lack of RFID system reliability)

Suriya, A. September 19, 2015, Slide 4 Start implementing from the simple scenario (indoor free space environment) with small facility 10*10m with 50 tags (items) which are randomly added to the system. Problem Description

Suriya, A. September 19, 2015, Slide 5 Problem Description Antennas with circular coverage pattern are used. Radius of the coverage is derived from Friis’s equation From the concept of the hexagonal packing -> the initial number of readers = 7 readers Select the location for 7 readers from 121 locations = 121!/(7!*114!) = 6.314e10 combinations !!!

Suriya, A. September 19, 2015, Slide 6 Problem Solution Apply the optimization techniques (Particle Swarm Optimization: PSO) to find the optimum placement of RFID reader antennas in warehouse to :  Maximize the coverage area within the warehouse facility (max. coverage area).  Minimize the number of RFID reader antenna (min. implementation cost).  Minimize the degree of overlap (min. interference).  Balancing the loads (tags) for each reader in the system (max. load balance) Multi-Objective functions

Suriya, A. September 19, 2015, Slide 7 Objective Function Multi-Objective functions -> Weighted Sum fitness = 0.4*coverage+ 0.2*interference + 0.2*cost + 0.2*load balance

Suriya, A. September 19, 2015, Slide 8 Some parameters of PSO need to be varied to achieve the best performance Results and Discussions 1) Inertia (w) : Large => global search, Small => local search w=0.9 gives the best performance

Suriya, A. September 19, 2015, Slide 9 Results and Discussions 2) Global social component (c1) : how much global best influences movement Local social component (c2) : how much local best influences movement c1=c2=0.7 gives the best performance

Suriya, A. September 19, 2015, Slide 10 Results and Discussions 3) Number of Particles nPar=30 gives the best performance

Suriya, A. September 19, 2015, Slide 11 Results and Discussions Parameters The most appropriate Values 1. The number of particles30 particles 2. The value of w, c1, and c2w = 0.9; c1 = c2 = The fitness function fitness = 0.4*coverage+ 0.2*interference + 0.2*cost + 0.2*load balance 4. The process for rounding the value of RFID placement location (coordinate) Rounding up 5. The number of iteration1,000 iterations 6. Total number of readers5 readers 4) Number of readers nReader = 5 gives the best performance

Suriya, A. September 19, 2015, Slide 12 Results and Discussions Reader 1 at site = 31 ( 8,2 ) Reader 2 at site = 87 ( 9,7 ) Reader 3 at site = 94 ( 5,8 ) Reader 4 at site = 26 ( 3,2 ) Reader 5 at site = 78 ( 0,7 ) Computation time = seconds Coverage = 1 Interference = 0.96 Cost = Load Balance = Fitness = At iteration=150

Suriya, A. September 19, 2015, Slide 13 The developed PSO in this simple scenario, the small facility area 10*10m consisting of 50 tags, can guide the search to a good solution with 100% coverage, low level of interference, and high load balance. These factor can improve the reliability of reader-tag communication and tags reading process. The optimum solution can be obtained with 5 readers -> less than the initial number of readers, i.e. 7 readers, derived from the concept of hexagonal packing. -> The company can save implementation cost. Applying optimization technique save a lot of time and the near-optimum solution can be achieved. Recommendations for further study and research All tags in the simple scenario are fixed location which sometimes is not practical in the real warehouse because it also has the mobile tags. Therefore, covering all entire area are needed. The RFID reader antenna tends to be more directional; thus, the elliptical shape of signal coverage have to be considered. The real warehouse has some obstacles which directly affect the signal propagation. This also needs to concern about to make the model more realistic. Conclusions

Suriya, A. September 19, 2015, Slide 14 Thank you for your attention Questions and Suggestions