Collision-aware composite hypothesis testing in random-access WSNs with sensor censoring

Abstract

We consider a distributed composite hypothesis testing problem in which sensor nodes share a collision channel to send their decisions and the fusion center (FC) has a limited time to collect these decisions. When the FC does not have enough time to collect all local decisions successfully, we propose a transmission protocol called sensor censoring random access as the multiple access scheme used by sensor nodes to send their decisions to the FC. By using this protocol, the collection time is divided into frames, where each frame consists of a number of time slots. The sensor nodes whose observations are within a specific range will send their decisions in a specific frame by using slotted ALOHA. Thereafter, we derive a Rao test used by the FC to decide whether the event is happening. Since this Rao test is aware of packet collisions and exploits them to make a global decision, we call it a collision-aware Rao test (CA-Rao test). Its asymptotic performance (the probabilities of detection and false alarm) is determined. The receiver operating characteristics of the CA-Rao test are evaluated and compared to those of a Rao test of distributed detection using parallel access channels.

Collision-aware distributed detection with population-splitting algorithms

“…With properly revising a transmission strategy such that the packet collisions will be from the same data, a packet collision indicates two or more sensor nodes have the same data. As a result, the packet collisions can be used in making a final decision [27][28][29][30]. Similarly, in the proposed PSRA, since the data bits sent in the same frame will be from the observations in the same level, the collision time slots in each frame are meaningful and will be used in making a final decision.…”

“…A key design is that, with properly revising a transmission strategy and a random access protocol such that the packet collisions will be from the same local decisions, a packet collision indicates two or more sensor nodes have the same decision. As a result, the packet collisions are informative [27][28][29][30]. The main contributions and results of this paper can be summarized as follows.…”

“…Transmission protocols based on population-splitting algorithms for distributed detection/estimation have been studied in [29,36,37], where the sensor nodes will share a collision channel to send their decisions. By using these protocols, the observation range is divided into M levels and the collect time is divided into M frames.…”

“…The FC observes the time-slot states to make a final decision or compute an estimate. The transmission protocol proposed in this paper is different from those in [29,36,37] as follows. Here, we apply the sensor-censoring strategy to a population-splitting algorithm, where the observation range is divided into censored regions (unreliable observations) and uncensored regions (reliable observations).…”

Decision fusion for composite hypothesis testing in wireless sensor networks over a shared and noisy collision channel

“…Distributed detection whose FC recognizes the collision time slots, in addition to the idle time slots and successful time slots, and exploit them in final decision-making has been investigated and analyzed in many scenarios: the Neyman–Pearson framework, 28 the sequential probability ratio test, 35 and the Rao test. 36,37 In our initial work, 36,37 no channel errors have been considered and only the Rao test fusion rules for the slotted-Aloha-based distributed detection were derived. On the contrary, in this article, we comprehensively derives and extensively compares fusion rules based on the GLRT, Rao test, and Wald test for both the TDMA-based distributed detection and slotted-Aloha-based distributed detection, where channel errors exist.…”