In the example above, the so-called high priority stream employs QPSK modulation and is designed to cover the whole service area.
We, eventually, propose an enhancement to the afore-mentioned scheme that takes advantage of the good radio conditions of users who are close to the base station to send them an additional stream using hierarchical modulation.
Table 2 System parameters Chip rate 4.096 ×106 cps Number of subcarriers (F) 64 Number of subcarriers per group (K) 2 or 4 Number of subcarriers groups 32 or 16 CP length 5 (Chan. A /20 (Chan. B) Number of symbols per data stream (N) 10 Modulation QPSK.
and a congruent animal sound affected object processing at a relatively early stage in the information-processing stream: a visual modulation of the N1 component when sound was added.
Before assigning the HP and LP streams to Hierarchical Modulation constellation points, we can decrease the bit error probability of the streams by using standard coding techniques such as convolutional coding.
Adaptive FEC provides considerable performance improvement for all fixed modulation streaming systems.
For the football sequence, the adaptive modulation streaming provided a 0.47 to 2.55 dB gain in the average PSNR.
The allocation algorithm takes into consideration not only the distance between partitioned blocks (hop count) but also the utilization of each block, in attempt to make the proposed MPSoC-based QAM modulator able to achieve robust performance under different incoming rates of data streams and different modulation levels.
Second, the average uncoded BERs of the two streams are comparable with BPSK modulation, while the first stream has better average uncoded BER than that of the second stream with QPSK and 8PSK modulations.
The fundamental idea is to gather the member stations located at the same network region and to transmit the stream with possibly high modulation and coding rates.
Note that mutually correlated source signals arise from encoding operations on the bit stream including channel coding, modulation, and space-time coding at a transmitter [7, 32].
