Opportunistic Transmission using Large Scale Channel Effects

This paper quantifies the multi-user wireless diversity benefit of basing opportunistic transmission on large scale shadowing. This technique is primarily aimed at wireless sensor nodes. The processing capability of these nodes is limited and transmissions between sensor nodes are very sporadic. It is therefore easier for these devices to track large scale shadowing variations than the small scale shadowing variations normally used for opportunistic transmission. This paper will derive closed form expressions that compare the average SNR improvement provided by opportunistic transmission when based on large scale and small scale channel effects. Closed form bit error rate (BER) expressions will also be used to illustrate that opportunistic transmission based on shadowing can achieve very good performance improvements for modestly sized scheduling groups and realistic indoor shadowing standard deviation values.