  This paper studies the problem of transmitting multiple independent layered
video streams over single-hop wireless networks using network coding (NC). We
combine feedback-free random linear NC (RLNC) with unequal error protection
(UEP) and our goal is to investigate the benefits of coding across streams,
i.e. inter session NC. To this end, we present a transmission scheme that in
addition to mixing packets of different layers of each stream (intra-session
NC), mixes packets of different streams as well. Then, we propose the
analytical formulation of the layer decoding probabilities for each user and
utilize it to define a theoretical performance metric. Assessing this
performance metric under various scenarios, it is observed that inter-session
NC improves the trade-off among the performances of users. Furthermore, the
analytical results show that the throughput gain of inter-session NC over
intra-session NC increases with the number of independent streams and also by
increasing packet error rate, but degrades as network becomes more
heterogeneous.
