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Details

Autor(en) / Beteiligte
Titel
Two-dimensional code acquisition in environments with a spatially nonuniform distribution of interference: algorithms and performance
Ist Teil von
  • IEEE transactions on wireless communications, 2004-01, Vol.3 (1), p.1-7
Ort / Verlag
Piscataway, NJ: IEEE
Erscheinungsjahr
2004
Link zum Volltext
Quelle
IEEE/IET Electronic Library (IEL)
Beschreibungen/Notizen
  • In this paper, we investigate code acquisition in the delay and angular domain in environments where interference and noise are nonuniformly distributed in the spatial (angular) domain. It is seen that performance is clearly degraded by the presence of nonuniform spatial distributions of interference. The degree of impairment is related to the actual shape of the distribution and becomes more significant when large amounts of interfering power are concentrated in one or more angular directions. As compared to a reference case with a uniform distribution of equivalent interfering power, the mean acquisition time could increase by factors of up to four. Some effective approaches to compensate for the loss of performance due to the uneven nature of interference are also studied. First, the effect of search strategies in the delay and angular domains on acquisition performance is assessed. A searching algorithm up-ranking angular cells according to the amount of associated interference is proposed as one solution to reduce the performance gap. It is shown that applying this search strategy can considerably reduce the mean acquisition time. Finally, two adaptive schemes based on setting integration times or threshold values according to the level of interference prevailing in each angular cell, are discussed. The former approach returns performance figures similar to those obtained with the uniform equivalent interference distribution while the latter provide moderate performance gains.

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