E??“04
1.E??“03
1.E??“02
1.E??“01
1 2 3 4 5 6
Covariance Matrix Estimated Rank
BER
STE (T/2-Spaced), MMSE, Flat Fade
STE (T/2-Spaced), MMSE, FSF (t = T)
FIGURE 6.13 Fractionally spaced STE matrix rank investigation.
flat-fading channel the covariance matrix rank is shown to be 3 and increased to 4 when a second ray
is inserted with significant delay.
6.2.3 Frequency Selective Fading CCI Environment
In this section, we consider a two-ray model plus interference that contains delay spread as well. This
is modeled as follows with i(k) representing the interfering signal.
(6.63)
(6.64)
Given the results of the previous sections we can immediately write down the MMSE array weights
given as
(6.65)
which can also be written as
(6.66)
In looking at this array weight we have the following comments to make: H1A is the desired channel
matrix of the first arriving ray, H1B is the desired channel matrix of the second arriving ray, H1C
and H1D are the cross terms relating to the first and second arriving rays of the desired signal.
Similarly, HIA is the interfering channel matrix of the first arriving ray, HIB is the interfering channel
matrix of the second arriving ray, and HIC and HID are the cross terms relating the first and second
arriving rays of the interfering signal.
Pages:
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515