Optimal rate allocation in progressive joint source-channel coding for image transmission over CDMA networks

This paper presents an optimal rate allocation scheme in joint source-channel coding (JSCC) for image transmission over CDMA networks. Our scheme first uses progressive joint source-channel codes [V. Stankovic et al., Sep. 2002] to generate operational transmission rate-distortion (TR-D) functions of different multiple-access channels with different BERs. The Lagrange multiplier is then employed to set the optimal rate allocation among different channels, subject to a total transmission rate constraint. Progressive JSCC offers the scalability feature that is very attractive for handling bandwidth variations in wireless communications. By extending the rate-distortion function in source coding to the TR-D function in JSCC, our work borrows the "equal slope" argument [Y. Shoham and A. Gersho, Sep. 1988] to effectively solve the rate allocation problem in JSCC for multi-channel image transmission. Experiments show that our scheme runs in real time and provides competitive performance at all intermediate transmission rates.

本文在联合源通道编码（JSCC）中提出了最佳速率分配方案，用于通过CDMA网络传输图像。我们的计划首先使用渐进的联合源通道代码[V. Stankovic等人，2002年9月，生成具有不同BER的不同多访问通道的操作传输率 - 渗透率（TR-D）函数。然后使用Lagrange乘数来设置不同渠道之间的最佳速率分配，但要受到总传输率约束。 Progressive JSCC提供了可伸缩性功能，该功能对于处理无线通信的带宽变化非常有吸引力。通过将源源函数扩展到源编码中的速率函数到JSCC中的TR-D函数，我们的工作借用了“相等的斜率”参数[Y。 Shoham和A. Gersho，1988年9月]，有效地解决了JSCC中的速率分配问题，以进行多通道图像传输。实验表明，我们的方案是实时运行的，并在所有中间传输速率上提供竞争性能。