MAC design and analysis for MU-MIMO and full-duplex enabled wireless networks
IEEE 802.11 based wireless networks, especially the infrastructure based Wireless Local Area Networks (WLANs) or Wi-Fi networks, are hugely successful, and have become an indispensable part of our life at homes and working places. However, the rapid growth of wireless devices, and a shift of users&#...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/283145 |
| Acceso en línea: | http://hdl.handle.net/10803/283145 |
| Access Level: | acceso abierto |
| Palabra clave: | MAC MU-MIMO Full-duplex IEEE 802.11 62 |
| Sumario: | IEEE 802.11 based wireless networks, especially the infrastructure based Wireless Local Area Networks (WLANs) or Wi-Fi networks, are hugely successful, and have become an indispensable part of our life at homes and working places. However, the rapid growth of wireless devices, and a shift of users' habit from web browsing to a wide variety of bandwidth-hungry applications (e.g., high-definition video, social network and cloud uploading), have made today's WLANs not only crowded, but also low at throughput. The latest IEEE WLAN amendment-802.11ac responds to these challenges by introducing a set of novel physical (PHY) and medium access control (MAC) features, including downlink multi-user Multiple-Input and Multiple-Output (MU-MIMO), higher modulation and coding scheme, channel bonding, frame aggregation, etc. Among them, downlink MU-MIMO is one of the most important features due to its potential to significantly improve the performance. It allows the access point (AP) to transmit frames to multiple stations (STAs) in parallel, which can substantially increase the network throughput, as well as to mitigate high collision rates. On the other side, recent research advances on the full-duplex (FD) transmission open another line to improve the performance of wireless network in dense areas. FD transmissions in wireless networks break the long-hold assumption that nodes can not transmit and receive simultaneously using the same frequency. This exciting progress not only promises a twofold capacity increase by allowing concurrent transmission and reception, but could also bring revolutionary changes to the MAC design by shaking the foundation of IEEE 802.11 medium access mechanism-Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). As CSMA/CA can become obsolete, and be replaced by the on-the-fly collision detection thanks to the FD's capability of simultaneous transmission and reception. However, these two lines of PHY advances (i.e., MU-MIMO and FD) do not directly translate to the useful performance gains at the MAC layer (e.g., the throughput increase). In order to take full benefits of MU-MIMO and FD, adaptations of the current IEEE 802.11 MAC protocols are needed. In this thesis, we first investigate the prominent MAC proposals in the literature, and then propose the required MAC adaptations to support MU-MIMO downlink and uplink transmissions separately. After that, we combine the downlink and uplink adaptations into a unified MU-MIMO MAC protocol to look into what influence would bring to the uplink or the downlink when both up/down-link traffic are present. We extensively evaluate the performance of the proposed protocol in saturated and non-saturated conditions to emulate the highly-densed scenario and the lightly-increased traffic scenario. Next, we model and evaluate the new IEEE 802.11ac standard MAC operations, and compare them with our proposals in a wireless mesh backhaul network. Afterwards, we utilize full-duplex technique and propose a full-duplex MAC (FD+) scheme to improve the performance of a wireless system. We analytically model FD transmissions and investigate what gains can be achieved at the MAC layer. Finally, we conclude our work and look into the future directions. Results from simulations and analytic models show that the significant performance gain can be achieved by extending traditional IEEE 802.11 MAC schemes to support MU-MIMO and FD transmissions. |
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