In this chapter
we will address the phase offset degradation.
If one were to blindly attempt to recover the information from the received symbols without compensating
for the phase offset present on the signal, then performance degradation will surely result.
If the receiver estimates the phase offset and compensates for it by derotating the received signal prior
to entering the detector then this is called coherent detection. On the other hand if no attempt is made
to estimate the received signal??™s phase offset and we extract the information from the received signal,
this is called noncoherent detection.
In digital communications there exist a few system design goals that we must mention prior to presenting
the choices available in the receiver, specifically modulation detection [1??“8]. These goals are
listed below (nonexhaustive):
??? Maximize transmission bit rate, Rb
??? Minimize Bit Error Rate, BER
??? Minimize required power, Eb/No
??? Minimize required system bandwidth, BW
??? Maximize system utilization/capacity, C
173
??? Minimize system complexity
??? Minimize power consumption
Being able to optimally choose the system values for each of the above parameters is a challenging
task. The suggested approach is to consider the system as a whole: transmitter, plus channel plus
receiver.
Pages:
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294