Impact of IEEE 802.11n/ac PHY/MAC High Throughput Enhancements on Transport and Application Protocols—A Survey

Abstract

Since the inception of Wireless Local Area Networks (WLANs) in the year 1997, it has tremendously grown in the last few years. IEEE 802.11 is popularly known as WLAN. To provide the last mile wireless broadband connectivity to users, IEEE 802.11 is enriched with IEEE 802.11a, IEEE 802.11b and IEEE 802.11g. More recently, IEEE 802.11n, IEEE 802.11ac and IEEE 802.11ad are introduced with enhancements to the physical (PHY) layer and medium access control (MAC) sublayer to provide much higher data rates and thus these amendments are called High Throughput WLANs (HT-WLANs). In IEEE 802.11n, the data rate has increased up to 600 Mbps, whereas IEEE 802.11ac/ad is expected to support a maximum throughput of 1 to 7 Gbps over wireless media. For both standards, PHY is enhanced with multiple-input multiple-output (MIMO) antenna technologies, channel bonding, short guard intervals (SGI), enhanced modulation and coding schemes (MCS). At the same time, MAC layer overhead is reduced by introducing frame aggregation and block acknowledgement technologies. However, existing studies reveal that although PHY and MAC enhancements promise to improve physical data rate significantly, they yield negative impact over upper layer protocols -mainly for reliable end-to-end transport/application layer protocols. As a consequence, a large number of schools have focused researches on HT-WLANs to improve the coordination among PHY/MAC and upper layer protocols and thus, boost up the performance benefit. In this survey, we discuss the impact of enhancements of PHY/MAC layer in HT-WLANs over transport/application layer protocols. Several measures have been reported in the literature that boost up data rate of WLANs and use aforesaid enhancements effectively for performance benefit of end-to-end protocols. We also point out limitations of existing researches and list down different open challenges that can be explored for the development of next generation HT-WLAN technologies.

Performance Analysis of IEEE 80.11ac Wireless Local Area Networks

“…The short guard interval (SGI) can effectively reduce the idle time in data transmission which consequently increases the throughput of the system. However, in dense networks with heavy traffic, the SGI option may cause more interference leading to degradation in the system throughput [5]. Beamforming is a technique used to optimize communications between access points (APs) and stations to respond to interference [3].…”

“…In contrast to 802.11n, all frames sent by 802.11ac devices must be in an A-MPDU format. The frame aggregation reduces the overhead and thus increases the system throughput [3], [5].…”

“…Simulation results are relatively close to the results of the theoretical model. The authors of [5] provide a survey on the impact of physical and MAC enhancements on transport and application layer protocols. A comparison between 802.11n and 802.11ac is also considered in [5].…”

“…The authors of [5] provide a survey on the impact of physical and MAC enhancements on transport and application layer protocols. A comparison between 802.11n and 802.11ac is also considered in [5]. In addition, the authors specify some challenges for 802.11ac in order to support higher layers protocols.…”

Evaluación de equipamiento de bajo coste para realizar medidas de red en entornos domésticos

“…Estos resultados sirven como medida inicial, antes de adquirir más dispositivos (lo que aumentaría el coste) con los que realizar medidas en paralelo y estudiar los fenómenos de competición de acceso al medio qué estos experimentarán. Sin embargo, no podemos olvidar que se están realizando avances mejorando las tecnologías de acceso WiFi, aumentando el ancho de banda disponible utilizando bandas y protocolos de acceso al medio diferentes [18], y se publican estudios sobre su impacto sobre los protocolos de transporte [19]. …”