Resource management for scalably encoded information: the case of image transmission over wireless networks

Scalable encoded information, as in the JPEG 2000 standard, results in files, which can be truncated at an arbitrary point and decoded. This work introduces a tractable, yet flexible model appropriate for resource management involving scalably encoded information. At its core is a function yielding a measure of "quality" of the decoded information as a function of the number of bits chosen for decoding. It is assumed that all that is known about this function is that its graph yields an "S-curve". An energy-efficient policy for the transmission over a wireless network of scalably- encoded images is sought. Two variables are jointly optimized: transmission power, and the number of bits of each file to be decoded ("coding rate"). The single-user case is fully analyzed, and a closed-form solution given, which can be clearly identified, graphically. The analysis indicates that both variables can be "decoupled", and their optimal values found independently of each other.