Scalar scheme for multiple user information embedding

Multiple watermarking is concerned with embedding several messages into the same host signal, with different robustness and transparency requirements. This paper proposes two implementable scalar schemes for multiple user "Dirty Paper Coding". The first -straightforward- approach consists in an independent superposition of two scalar Dirty Paper Coding schemes. The second consists in a joint design of a scalar Dirty Paper Coding. This joint approach is based on the ideal DPC scheme for Broadcast Channels with noncausal side information known to the transmitter. For this purpose, the "Scalar Costa Scheme" that has been originally conceived for one user is extended to two users. Performance evaluations, including Bit Error Rates and Capacity region curves are provided for both methods, illustrating the improvements brought by a joint design.