We also remark that the WZ feedback requires very few bits: in fact it just signals whether new WZ bits are required or not.
For mapping the encoders' outputs to 4CPFSK signals, the first and second bits are taken from the first and second level of turbo encoder output, respectively.
The 4-QAM "codeword" is then calculated as c = C 2 n ( i ) ( k ( i ) ) + j C 2 n ( q ) ( k ( q ) ), which is much like the result of coded modulation where groups of coded bits (in this case uncoded bits) are mapped to signal constellation points to improve spectral efficiency [20].
Therefore, assuming that approximately 60 bits are required for signaling each burst [2] and using a QPSK modulation with a code rate 1/3, the downlink signaling zone (i.e., the DL-MAP) would span less than 2 OFDM symbols.
Typically, a baseband signal resolution of more than 10 bits is required to meet the close-in spectrum and waveform quality specifications over the entire power control dynamic range as per the standard's requirements.
In order to leave as many receive levels as possible "free" for reception of signal bits, it will be advantageous if multiple interference bits fall on one receive level.
The RMSE and MAE differences between the images produced by native 14-bit raw signal and numerically truncated reduced-bit signal are shown in Fig. 5 bottom).
By multiplying the data signal with the spreading signal, each baseband information bit is spread to N c chips where N c is the number of spreading sequence samples.
Considering the symmetric structure of Gray-labeled PAM, we can resort to Lemma 3 to find the signal ({z_{overline {k}_{i}^{j}}}), which only requires the binary representation of index ({widehat k}^{j}) and addition operation, instead of computing the Euclidean distance between all the signals with the ith bit being opposite to that of ({z_{{{widehat k}^{j}}}}) and ℜ(r j ).
It is evident that for each allocation pattern used, a number of control signaling bits need to be transmitted additionally to the information symbols to notify the receiver which of the candidate allocations was selected.
