Energy consumption of wireless data transmission heavily depends on the shape of the outgoing traffic of the mobile device. In this paper, the authors propose a traffic scheduler that shapes the packets into consistent bursts based on per-packet performance constraints in order to reduce the overall transmission cost. Their scheduler takes into account the scenarios where multiple network applications run concurrently on the mobile device. They evaluate the traffic scheduler with real-life traffic traces from delay-sensitive applications, e.g. Internet radio and YouTube, and delay-tolerant applications e.g. Web browsing.