Accounting for all possible M-QAM
symbols, the total number of conditional subgroups formed for fingerprint generation is either M x [N.sub.SG] or M x [N.sub.SG]+1 if an "other" subgroup is required.
If S is the total number of available layers in eU-OFDM, the latency of eU-OFDM at the transmitter is greater than the latency of DCO-OFDM by a factor of 2S - 1 for the same M-QAM
modulations used on both systems.
Tabla 1 Inicio de la correccion de errores para cada modulacion QAM simulada M-QAM
[E.sub.b]/[N.sub.0] 16 9 32 11 64 13 128 15,5 256 18
But, for most non binary modulation techniques (e.g., M-QAM
and M-PSK) an exact expression for BER is hard to find.
Dai, "Effects of LO phase and amplitude imbalances and phase noise on M-QAM
transceiver performance," IEEE Transactions on Industrial Electronics, vol.
Like the DA case, we have observed the effect of varying constellation size as well as the bias of NDA estimator for various M-QAM
. The packet length l has been set to 1000 symbols for all cases.
In attaining the flat fading condition, the M-QAM
OFDM performance converged to the M-QAM
modulation and the code implemented on the DSP behaved as expected.
As is well known, the signal spaces supported on sinusoidal functions allow us to obtain, at most, two orthogonal functions for the symbol period (as occurs in M-QAM
To improve spectral efficiency, we introduced adaptive LDPC coded modulation (ACM) at source node which provides multiple coded modulation transmission schemes (CMSs), where each scheme is specified by one of the M-ary quadrature amplitude modulation (M-QAM
) and LDPC code pair.
Although, it is generally a sub-optimal modulation scheme, compared to other M-QAM
constellations, in the sense that they do not maximally space the constellation points for a given energy.
Chandra  derived the closed form series solution for B- PSK, B-FSK, DB-PSK and M-QAM
over Rician fading channels.
Therefore, the improved PER calculation for M-QAM
scheme for gray mapping, was expressed by Equation (2) .