Towards probabilistic arbitration in sensors integration

The purpose of this paper is to model an important aspect of the problem of sensor information integration that arises in wireless communications, where N sensors try to communicate with a receiver using a single un‐shareable radio channel. If several sensors transmit at the same time, their transmissions collide at the receiver resulting in garbled messages and the need for re‐transmission. This is highly undesirable since the sensors are energy‐constrained and the radio interface is known to be the most significant source of energy expenditure. Consequently, it is of paramount importance to design arbitration protocols that are highly efficient in stamping out collisions and that are, at the same time, as lightweight as possible.

The receiver advertises a time division multiple access (TDMA) frame consisting of n slots, numbered from 1 to n, where n is an application‐dependent parameter. Each sensor generates uniformly at random, and independently of other sensor, an integer i between 1 and n and transmits in the i‐th slot of the TDMA frame. If two or more sensors are transmitting in the same slot their messages will be lost to collision. Similarly, slots that carry no transmission are wasted. The authors model the arbitration strategy discussed above as a Bose‐Einstein occupancy problem where N indistinguishable balls are thrown at random into n distinguishable bins and all distinguishable outcomes are considered to be equally likely.

In this paper the authors present a distributed probabilistic mechanism that aims to arbitrate between several competing requests by various sensors for the radio channel. The mechanism is simple, energy‐efficient and does not rely on the existence of unique sensor identifiers (IDs).

The Bose‐Einstein occupancy model presented in this paper will help the receiver to tailor an appropriate number of timeslots in TDMA frame during the integration process, such that collisions are minimized, and hence integration between sensors can be done effectively.