@article{redieteab_2013, 
  title={Cross-layer Optimization for Next Generation Wi-Fi}, 
  abstractNote={From the initial 1997 specification to the undergoing IEEE 802.11ac
standardization, a leap in throughput has been observed with every new
generation. The expectations for next generations on issues like throughput,
range, reliability, and power consumption are even higher. This is quite a
challenge considering all the work already done. Cross-layer optimization of
physical (PHY) and medium access control (MAC) layers can be an interesting
exploration path for further enhancement. During this thesis we have studied
cross-layer optimization techniques, with a focus on the IEEE 802.11ac
standard. A new multichannel aggregation scheme involving cross-knowledge
between PHY and MAC layers has been proposed to improve performance in
collision-prone environments. We have shown that some functionalities directly
involved PHY and MAC layers. An accurate modeling of both PHY and MAC
mechanisms is thus needed to have a realistic characterization of such
functionalities. A cross-layer simulator, compliant with IEEE 802.11ac
specifications, has thus been implemented. To the best of our knowledge, this
is the first simulator incorporating detailed PHY and MAC functionalities for
the IEEE 802.11ac standard. The multiple-user multiple-input, multiple-output
(MU-MIMO) technique, which is one of the main innovations of the IEEE 802.11ac,
needs both PHY and MAC layer considerations. We have thus used the implemented
cross-layer simulator to evaluate the performance of MU-MIMO and compared it
with the single-user MIMO (SU-MIMO). The aim of these studies was to evaluate
the 'real' gains of MU-MIMO solutions (accounting for PHY+MAC) over SU-MIMO
solutions and not the generally accepted ones. The impact of the channel
sounding interval has particularly been studied. Finally, we have proposed a
short PHY layer version of acknowledgment frames for overhead reduction in IEEE
802.11ah communications.}, 
  author={Redieteab}, 
  year={2013}, 
  month={Jan}
  }