  The capacity of wireless networks is fundamentally limited by interference.
However, little research has focused on the interference correlation, which may
greatly increase the local delay (namely the number of time slots required for
a node to successfully transmit a packet). This paper focuses on the question
that whether increasing randomness in the MAC, such as frequency-hopping
multiple access (FHMA) and ALOHA, helps to reduce the effect of interference
correlation. We derive closed-form results for the mean and variance of the
local delay for the two MAC protocols and evaluate the optimal parameters that
minimize the mean local delay. Based on the optimal parameters, we propose the
definitions of two operation regimes: correlation-limited regime and
bandwidth-limited regime. Our results reveal that while the mean local delays
for FHMA with N sub-bands and for ALOHA with transmit probability p are the
same when p=1/N with thermal noise ignored, significant difference exists
between the variances. At last, we evaluate the mean delay-jitter tradeoff and
the bounds on the tail probability of the local delay, which shed key insights
into the system design.
