IEEE 802.11ax Wi-Fi
- the IEEE 802.11ax standard which is expected to speeds up to four times those available via IEEE 802.11ac.
IEEE 802.11ax is seen as the successor to 802.11ac. The new 802.11ax is still in its early stages of development, but it is anticipated that it will provide up to four times the speed of 11ah.
Another of the key issues that 802.11ax aims to resolve is that of mutual interference between different access points. In some densely covered areas this is significantly slowing down the networks. Solving this issue rather than just providing bearers for faster data rates will have a greater effect on real throughput.
Comparatively few details have emerged yet about the actual specification, and the technology for IEEE 802.11ax, but some details have emerged.
IEEE 802.11ax basics
There are a number of technologies involved in 802.11ax
- OFDA It is anticipated that the system will be based around and OFDM based system. OFDA, orthogonal frequency division access, has been mentioned, but exact details will come clear in due course. OFDM is often sued for high data rate systems because of its resilience to channel irregularities. OFDM is very resilient to the effects of selective fading. It also provides excellent spectral efficiency. According to Huawei, OFDA increases the theoretical spectral efficiency by 10 times, but in real world scenarios this is likely to be somewhat less, possibly around 4x for IEEE 802.11ax.
- MIMO MIMO is currently used in many Wi-Fi and mobile telecommunications systems. For 802.11ax the working group is considering state-of-the-art technologies including uplink MU-MIMO.
- Frequency bands Current thinking is the 802.11ax will operate in the 2.4 and 5 GHz ISM bands.
- Full duplex radio Full duplex radio is being considered for 802.11ax as this will provide additional improvements in spectral efficiency.
- OBSS interference handling The use of OBSS ,overlapping basic service sets interference handling techniques is being considered as a way of improving performance. This may take one or more of many forms including some form of beamforming reception, etc. . With increasing numbers of APs being deployed spectrum management and interference mitigation from adjacent access points is of increasing importance.
A BSS is a Basic Service Set. This is a key component for the IEEE 802.11 WLAN architecture. This network architecture is built around a Basic Service Set which is actually a set of STAs (the component that connects to the wireless medium such as a network adapter or NIC) that communicate with each other. When one access point is connected to wired network and a set of wireless stations it is referred to as a Basic Service Set or BSS.
The development of IEEE 802.11ax is still in its early stages. It is not anticipated that it will be available for some time yet. The first draft specification may be available in 2016, and possibly the first hardware a year or two beyond that.
By Ian Poole
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