Multiaccess Channels with State Known to One Encoder: A Case of Degraded Message Sets

Abstract

Abstract-We consider a state-dependent multiple access channel p(y|x1, x2, s) whose output Y is controlled by the channel inputs X1 and X2 from two encoders and the channel state S. It is assumed that the channel state is known non-causally at one encoder, called the informed encoder. We derive the capacity region for the case of degraded messages in which the informed encoder knows the message of the uninformed encoder.

Cooperative Relaying With State Available Noncausally at the Relay

“…This upper bound is non-trivial and relates to the bounding technique developed in the context of multiple access channels with asymmetric channel state in [16,Theorem 2]; however, we note that the present upper bound is proved using techniques that are different from those in [16]. On a related note, we mention that at a high level there is a connection between the multiple access transmission part in the RC with informed relay in this work and the models in [13], [16]. However, there are also numerous conceptual differences that will be discussed whenever relevant.…”

“…The state-dependent MAC with some, but not all, encoders informed of the channel state is considered in [10], [13]- [16] and the state-dependent relay channel with informed source is considered in [18], [19]. For the Gaussian case of these models, the informed encoder applies a June 17, 2009 DRAFT slightly generalized DPC (GDPC) in which the channel input random variable and the channel state random variable are negatively correlated.…”

“…For example, to increase system spectral efficiency, collaboration has been investigated in the realm of cognition in [34]- [36]. Also, the problem of collaborative signal transmission in the presence of some cognizant terminals has been investigated for a MAC scenario in [13], [16] and for an interference channel scenario in [37]- [40]. The setup we consider in this paper also models the building block for collaborative wireless networks in which only the relays, but neither sources nor destinations, are cognizant of the channel state.…”

Dirty-Paper Coding for the Gaussian Multiaccess Channel With Conferencing

“…This leads us to the definition of achievable rate pairs and capacity region. A blocklength , powers code of rate pair is a triple , where and are of the form (6) and (7) and satisfy the power constraints (8) and (9), and where is of the form (10). We say that a rate pair is achievable if for every and every sufficiently large blocklength , there exists an -conference and a blocklength , powers code of rates exceeding such that the average probability of decoding error tends to 0 as tends to infinity, i.e., (11) The capacity region is defined as the set of all achievable rate pairs and is denoted by , or by for short.…”

“…Unlike our scenario, in these scenarios, the capacity region depends on whether the transmitters learn the interference before or after the conferencing. Multiaccess setups without conferencing where both transmitters know only parts of the interference were also studied in [9], [10], [14]- [16], [19]- [21], and [27].…”