Frequency rolling: a cooperative frequency hopping for mutually interfering wpans

A Wireless Personal Area Network (WPAN) provides wireless links among proximate devices,usually carried by an individual.As WPAN gains momentum in ubiquitous usage, the interference that collocated WPANs cause to each other, termed self-interference, becomes one of the major sources that degrade the communication performance of WPAN. This paper in roduces the Frequency Rolling (FR), a particular instance of frequency hopping (FH) that enables he collocated WPANs to cooperate and avoid the self-interference. The FR uses as input solely the observed packet error rate (PER) and it does not require any exchange of information among he collocated WPANs. The effect of the FR over a longer time in erval is hat the WPANs use he complete set of disposable channels in an implicit time-division and cooperative manner. The parameters of he FR are chosen such that a WPAN which uses FR never occupies the channels in the unlicensed spectrum more than what is permitted by the current regulation. We compare the goodput offered by FR to the goodput of the collocated piconets when conventional pseudorandom FH is used. Our simulation results show that FR has superior goodput performance. In addition, he design of FR is made robust owards the errors due to the channel noise. Some guidance for practical fault-toleran design and future extensions of FR are given. All hese features promote the great potential of FR as a coexistence mechanism for unlicensed operation.