Performance of CSMA and TDMA protocols for break-in channel access in a frequency hopping (FH) narrowband high frequency (HF) blocked channel environment

Hong, Yoon; Miller, D. R.

doi:10.1109/milcom.1993.408716

Cited by 2 publications

(1 citation statement)

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“…Due to its spectral efficiency, OFDM is an attractive physical layer waveform for ad hoc networking, but OFDM's sensitivity to synchronization error requires accurate time and frequency offset estimation [2]. When establishing node-to-node link connectivity, with maximum distance and high probability, it is critical to minimize channel access time in carrier sense multiple access (CSMA) and packet re-transmissions in time division multiple access (TDMA) networks [3] . If CSMA channel access is not robust, nodes requesting to send data spend excessive amounts of time attempting channel access and may cause excessive co-<:hannel interference (CCI) [4].…”

Section: Introductionmentioning

confidence: 99%

Synchronization for broadband OFDM mobile ad hoc networking: Simulation and implementation

Kleider

Gifford

2002

IEEE International Conference on Acoustics Speech and Signal Processing

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Broadband wireless services are typically considered usable in limited mobility conditions (fixed access or at pedestrian speeds). In this paper, we present a method for time and frequency syn chronization of broadband OFDM for mobile ad hoc networking systems, where each node randomly and rapidly changes loca tion. The proposed method is robust in Rayleigh fading and is computationally tractable for low-power digital signal processor (DSP) implementations. The synchronization method uses a pseudo-noise (PN) preamble sequence, provides low probability of false detection, low probability of missed detection, and ex hibits a low peak-to-average power ratio (pAPR). We show that the power spectral density (PSD) of the PN-based preamble, after the digital up-converter shaping filter, fits into a spectral mask similar to that of the OFDM traffic signal's PSD. Efficient im plementation is demonstrated using frequency-domain equivalent processing on a fixed-point Texas Instruments DSP and a float ing-point Motorola G4 PowerPC with Altivec.0-7803-7402-9/02/$17.00 �2002 IEEE

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Section: Introductionmentioning

confidence: 99%