Multi-channel Wi-Fi

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Multi-channel Wi-Fi: advanced implementation of standards compliant Wi-Fi delivering multiple concurrent channels of transmit and receive from a single radio

Applications

Designed to increase spectrum utilization in high client and / or high station density environments, the delivery of multiple concurrent channels can result in fewer retransmissions, lower error rates, lower latency and higher aggregate throughput compared to implementations which rely on spatial diversity, channel bonding, complex modulation and coding schemes.

Channel bonding, used in Very High Throughput (VHT) or 802.11 AC 802.11AC / 802.11 AX [1] implementations, requires channel widths up to 80 MHz or 160 MHz. According to the IEEE Research Paper, IEEE 802.11ac: Effect of Channel Bonding on Spectrum Utilization in Dense Environments, the reliance on wider channels decreases the number of channels available in a given area and in high client or high station density environments, results in lower throughput per client (source).

When wider channels are not available in applications of density or interference, the IEEE 802.11 standard, or WiFi, will back-off to a narrower 20 MHz wide channel. This is predominately the case in high-density applications such as stadiums, public areas, venues etc, and is increasingly faced by home applications where repeaters or mesh deployments are used in an effort to support multiple devices (Roku, AppleTV, IoT devices etc)

Implementation Challenges

Implementation of multi-channel requires the use of advance interference mitigation techniques to overcome two main types of interference:

Co-Channel Interference (CCI)

Co-channel interference or CCIis crosstalk from two different radio transmitters using the same frequency.

Adjacent Channel Interference (ACI)

Adjacent-channel interference ACI is interference caused by extraneous power from a signal in an adjacent channel. ACI may be caused by inadequate filtering (such as incomplete filtering of unwanted modulation products in FM systems), improper tuning or poor frequency control (in the reference channel, the interfering channel or both).

ACI is distinguished from crosstalk.[1]

Advantages and Limitations

Advantages

Higher channel density in a given area can deliver the following key benefits: Reduction in error rates

Lower retransmission rates

Decreased latency

Increased aggregate throughput

Higher performance for attenuated clients

Limitations

Spectrum allocations and limits are not consistent worldwide Use of multiple channels requires professional network planning and installation

Wi-Fi

https://www.everythingrf.com/community/what-is-wifi3

Links

[[ https://en.wikipedia.org/wiki/Wi-Fi ]] [[ https://en.wikipedia.org/wiki/IEEE_802.11 ]] [[ https://en.wikipedia.org/wiki/Wi-Fi_Alliance ]] [[ https://en.wikipedia.org/wiki/Adjacent-channel_interference ]] [[ https://en.wikipedia.org/wiki/Co-channel_interference ]]

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