Modeling of the code acquisition process for Rake receivers in CDMA wireless networks with multipath and transmitter diversity

In this paper, we present models for the code acquisition process in Rake r eceivers. These models include multipath diversity, multiple transmitter (b ase station or satellite) diversity, and multiple access interference gener ated by other users in the network, This results in a different probability of false alarm for each cell of the code delay uncertainty region. The ana lysis is based on signal flow graph theory By using these models, we elabor ate different strategies for Rake receiver synchronization and derive exact closed-form results for the average acquisition time. These strategies dif fer in how they organize initial (first Rake finger) and postinitial search algorithms. If the channel is known, the initial synchronization may organ ize a parallel search for all fingers simultaneously by a proper set up of the local correlators' mutual delays. If not, then a serial search of diffe rent segments (partitioned among the different fingers) can be organized. I n the postinitial search, sequential or random initializations are possible . A set of approximations is also included for practical applications where a quick assessment of the system performance is needed.