Reduced Complexity Power Minimization Algorithm for DMT Transmission - Application to Layered Multimedia Services over DSL

This paper presents an original bit and power loading algorithm for discrete multi tone data transmission of layered multimedia services. The proposed method, based on the waterfilling principle, realizes the bit allocation directly from a non iterative LUT-based solution compared to classical loading algorithms. First, the method is described in the single layer case. Then, the method is extended for multiple services transmission. Each service is characterized by its own quality of service (QoS) requirement and the bit and power allocation minimizes the total power consumption under bit rates and bit error rates constraints. In this case, the simultaneous transmission of the multiple services is achieved using a frequency division multiplexing (FDM) scheme, and the method used to assign different layers to subchannels is detailed. Experimental results of video delivery over ADSL show that the proposed algorithm comes near the optimal solution (the increase of power is lower than 0.2 dB) whereas its computational complexity is lower than traditional loading algorithms.