Method of communicating in a radio frequency identification system using aloha networks

Abstract

A method is presented for taking an unknown field of transponders and converting them to a slotted Aloha architecture and increasing the throughput allowed by the slotted Aloha architecture by using several different techniques including shortening the time of empty and collided timeslots, implementing a unique random number generator that creates random numbers that are uniquely based on an individual tags location, and on an ability to estimate the total number of transponders and control the offered rate such that throughput is always maximum. While these techniques work well together and produce the most benefit when used together, they are independent techniques and any one may be used alone without the others. Thus a system might use the estimated total number of transponders technique and the timeslot shortening technique, but use a standard random number generator rather one based on transponder location with only a small decrease in overall performance.