| 摘要 |
<p>A method of obtaining N values of a constellation ratio (alpha) for use when transmitting a hierarchical modulation (HM) signal comprises obtaining a model of the variation in a minimum signal-to-noise ratio (SNR) , as a function of alpha, required to provide a predetermined performance measure at a receiver ; selecting N target SNR values, and obtaining each of the N values of alpha, based on the model, by obtaining the value of alpha corresponding to each of the target SNR values. The model may be obtained by measurement or simulation. The performance measure can be e.g. bit error rate, packet error rate, or block error rate. Information identifying the selected value of alpha can be included in the transmitted signal. Applications include Digital Video Broadcasting (DVB), including Next Generation Handheld (NGH) systems.</p> |
