Conference Paper

Pre-RAKE diversity combination for direct sequence spread spectrum communications systems

Dept. of Electr. Eng., Keio Univ., Yokohama
DOI: 10.1109/ICC.1993.397307 Conference: Communications, 1993. ICC 93. Geneva. Technical Program, Conference Record, IEEE International Conference on, Volume: 1
Source: IEEE Xplore

ABSTRACT A novel method of multipath diversity signal combination is
proposed for mobile direct sequence spread spectrum (DS-SS)
communications. Multiple transmissions are made for each spread signal.
Each transmission is independently delayed and amplified in the complex
domain according to the delay profile and the estimated path strength of
the channel. This is done to facilitate reception of a signal at the
mobile unit which is already a RAKE combination of the multipath
signals. This method is called a pre-RAKE combination system because the
RAKE combination function is performed pre-transmission. Using this
method the size and complexity of the mobile unit can be kept to a
minimum. The pre-RAKE method retains the advantages of diversity
reception in a multi-path fading environment. An examination of the SNR
for the traditional RAKE and the pre-RAKE systems and computer
simulations show that the performance of the pre-RAKE system is
equivalent to that of the RAKE system

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