  Reuse-1 systems operating in the sub-1 GHz UHF band are limited by
substantial co-channel interference (CCI). In such orthogonal frequency
division multiple access (OFDMA) cellular systems, the inter-sector or
inter-tower interference (ITI) makes accurate signal recovery quite challenging
as sub-1 GHz bands only support single-input single-output (SISO) links.
Interference-aware receiver algorithms are essential to mitigate the ITI in
such low-frequency bands. Such algorithms enable ubiquitous mobile broadband
access over the entire homeland, say with >95% geographical coverage with
quality of service guarantees. One element of the interference-aware signal
recovery is the least-squares-based joint channel estimation scheme that uses
non-orthogonal pilot subcarriers. This estimator is then compared with a
variant that uses orthogonal pilot subcarriers to bring out the advantage of
this joint estimator. It is shown that the proposed joint estimator requires
fewer pilots to be well-determined when compared to its under-determined
orthogonal counterpart. Moreover, it is easy to implement and does not require
any knowledge of channel statistics. This work also derives a compensation
factor needed for the interference-aware detector in the presence of
inter-carrier interference (ICI) originating from multiple transmitters.
Simulation results show that the proposed joint channel estimator outperforms
traditional estimators at moderate to high frequency selectivity. The proposed
compensation factor to the joint detector is found to be essential for
recovering the transmitted signal in the absence of phase-tracking pilots.
