  We present an analytical framework to assess the link layer throughput of
multichannel Opportunistic Spectrum Access (OSA) ad hoc networks. Specifically,
we focus on analyzing various combinations of collaborative spectrum sensing
and Medium Access Control (MAC) protocol abstractions. We decompose
collaborative spectrum sensing into layers, parametrize each layer, classify
existing solutions, and propose a new protocol called Truncated Time Division
Multiple Access (TTDMA) that supports efficient distribution of sensing results
in "k out of N" fusion rule. In case of multichannel MAC protocols we evaluate
two main approaches of control channel design with (i) dedicated and (ii)
hopping channel. We propose to augment these protocols with options of handling
secondary user (SU) connections preempted by primary user (PU) by (i)
connection buffering until PU departure and (ii) connection switching to a
vacant PU channel. By comparing and optimizing different design combinations we
show that (i) it is generally better to buffer preempted SU connections than to
switch them to PU vacant channels and (ii) TTDMA is a promising design option
for collaborative spectrum sensing process when k does not change over time.
