Abstract:
The future tactical systems require network based seamless communication with precise, ac-
curate and reliable information. To achieve this end, a multi-mode high throughput CDMA-
based wideband networking waveform for software de ned radio is proposed. The proposed
waveform has several di erent modes of operation and the maximum achievable throughput
of 17.2 Mbps. Novel algorithms for the waveform's physical layer transmitter and receiver
including sampling clock recovery, burst detection, and carrier frequency o set estimation
and compensation are proposed. For Sampling clock recovery, a novel three stage Mod-
i ed Square Timing Recovery (MSTR) algorithm is proposed. For burst detection, two
novel algorithms based on Time Domain Repetitive (TDR) and Di erentially Modulated
(DM) training sequences are proposed. For carrier frequency o set estimation, a novel
algorithm based on modi ed FFT and quadratic interpolation is proposed. A novel two
stage carrier frequency o set estimator with improved performance is also proposed which
consists of Maximum Likelihood Data Aided (MLDA) estimation and Sample-by-Sample
Residual O set (S2RO) estimation stages. To reduce the packet re-transmissions overhead
and achieve better throughput, a novel link adaptation technique is proposed, which is based
on fuzzy inference system by considering Quality of Service and throughput requirement
of user/application. The throughput adaptation is achieved by changing the modulation
technique and the number of multicodes assigned to each user. The novelty of the pro-
posed algorithms is selected by considering the implementation a nity. The performance
improvement of the proposed algorithms is demonstrated by comparing them with a set of
known existing methods. It is shown through simulation results that the proposed algorithms
are superior in terms of performance, throughput and computational complexity. The pro-
posed algorithms are implemented using Field Programmable Gate Array and Digital Signal
Processor on SDR platform. Actual results from hardware are compared and veri ed with
the simulation results to demonstrate the e ectiveness of the proposed techniques. This
iv
wideband SDR waveform based on the proposed algorithms nds many real world applica-
tions in both the tactical and commercial scenarios. Some examples include biometrics,
video conferencing, IP data, le transfer, situational awareness, messaging, voice push to
talk, simultaneous voice and data transfer.
