  Throughput capacity is a critical parameter for the design and evaluation of
ad-hoc wireless networks. Consider n identical randomly located nodes, on a
unit area, forming an ad-hoc wireless network. Assuming a fixed per node
transmission capability of T bits per second at a fixed range, it has been
shown that the uniform throughput capacity per node r(n) is Theta((T)/(sqrt{n
log n})), a decreasing function of node density n.
  However an alternate communication model may also be considered, with each
node constrained to a maximum transmit power P_0 and capable of utilizing W Hz
of bandwidth. Under the limiting case W rightarrow infinity, such as in Ultra
Wide Band (UWB) networks, the uniform throughput per node is O ((n log
n)^{(alpha-1}/2}) (upper bound) and Omega((n^{(alpha-1)/2})/((log n)^{(alpha
+1)/2})) (achievable lower bound).
  These bounds demonstrate that throughput increases with node density $n$, in
contrast to previously published results. This is the result of the large
bandwidth, and the assumed power and rate adaptation, which alleviate
interference. Thus, the effect of physical layer properties on the capacity of
ad hoc wireless networks is demonstrated. Further, the promise of UWB as a
physical layer technology for ad-hoc networks is justified.
