  This work considers the problem of communication from a single transmitter,
over a network with colocated users, through an independent block Rayleigh
fading channel. The colocation nature of the users allows cooperation, which
increases the overall achievable rate, from the transmitter to the destined
user. The transmitter is ignorant of the fading coefficients, while receivers
have access to perfect channel state information (CSI). This gives rise to the
multi-layer broadcast approach used by the transmitter. The broadcast approach
allows, in our network setting, to improve the cooperation between the
colocated users. That is due to the nature of broadcasting, where the better
the channel quality, the more layers that can be decoded. The cooperation
between the users is performed over an additive white Gaussian channels (AWGN),
with a relaying power constraint, and unlimited bandwidth. Three commonly used
cooperation techniques are studied: amplify-forward (AF), compress-forward
(CF), and decode-forward (DF). These methods are extended using the broadcast
approach, for the case of relaxed decoding delay constraint. For this case a
separated processing of the layers, which includes multi-session cooperation is
shown to be beneficial. Further, closed form expressions for infinitely many AF
sessions and recursive expressions for the more complex CF are given. Numerical
results for the various cooperation strategies demonstrate the efficiency of
multi-session cooperation.
