ENC3250 Solutions pg 50

ENC3250 Solutions - increases only gradually does the system degrade to the point of an unacceptable error rate 10.11 Self-jamming Unless all of

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-50- increases; only gradually does the system degrade to the point of an unacceptable error rate. 10.11 Self-jamming: Unless all of the mobile users are perfectly synchronized, the arriving transmissions from multiple users will not be perfectly aligned on chip boundaries. Thus the spreading sequences of the different users are not orthogonal and there is some level of cross-correlation. This is distinct from either TDMA or FDMA, in which for reasonable time or frequency guardbands, respectively, the received signals are orthogonal or nearly so. Near-far problem: Signals closer to the receiver are received with less attenuation than signals farther away. Given the lack of complete orthogonality, the transmissions from the more remote mobile units may be more difficult to recover. Thus, power control techniques are very important in a CDMA system. Soft handoff: A smooth handoff from one cell to the next requires that the mobile acquire the new cell before it relinquishes the old. This is referred to as a soft handoff, and is more
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This note was uploaded on 02/20/2012 for the course ENC 3250 taught by Professor Dr.timothycerner during the Fall '11 term at UNF.

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