Chapter 4
Wi-Fi Connectivity
Wi-Fi networks are the most widely used wireless computer networks in the world. They have become indispensable for connecting our devices to the internet whether we are at home, in the office, or using public internet hotspots.
Wi-Fi or wireless LAN systems are based on the IEEE 802.11 family of standards. Each standard serves a specific application area:
- 802.11a/b/g/n/ac/ax/be are the most familiar standards used for high-speed internet connectivity around the home or office.
- 802.11ad/ay are intended for short-range high-throughput applications such as streaming digital video between a TV and phone.
- 802.11az is for next -generation positioning and super-resolution ranging.
- 802.11ah is a sub-1 GHz long-range, low-power Wi-Fi variant for IoT applications.
- 802.11p/ba is used for vehicular communications (V2X).
| Standard | Bandwidth (MHz) | MIMO | Designation |
| 802.11ax | 20,40,80,160 | OFDMA and MU-MIMO | HE High Efficiency |
| 802.11ad | 2160 | Beamforming | DMG Directional Multi-Gig. |
| 802.11ac | 20,40,80,160 | Up to 8 spatial streams, MU-MIMO | VHT Very High Throughput |
| 802.11n | 20,40 | Up to 4 spatial streams | HT - High Throughput |
| 802.11ah | 1,2,4,8,16 | MU-MIMO | S1G |
| 802.11g | 20 | N/A | Non-HT |
| 802.11a | 5,10,20 | N/A | Non-HT |
| 802.11b | 20 | N/A | Non-HT |
| 802.11p | 5,10 | N/A | Non-HT |
| 802.11j | 10 | N/A | Non-HT |
Wi-Fi system design challenges are very similar to those of cellular networks.
Waveform Generation
To ensure Wi-Fi systems conform to the IEEE 802.11 specifications, it is essential to generate waveforms for the supported family of standards. Using the Wireless Waveform Generator app, available with WLAN Toolbox™, makes waveform generation easy and interactive.
System-Level Simulations
Wi-Fi system designers need to model communication links with multiple nodes. Wi-Fi systems operate across a protocol stack that includes physical (PHY), medium access control (MAC), and application layers. Designers need to measure quantities such as throughput, latency, interference, and packet loss at the node and network levels. They also need to investigate the coexistence of WLAN signals with other signals such as Bluetooth, 5G, and LTE.
Positioning and Localization
The IEEE 802.11az standard is commonly used as next-generation technology for high-resolution indoor positioning. Designers need to effectively extract temporal information, such as time of arrival (ToA), or spatial information, such as angle of arrival (AoA), from a multipath signal to compute a distance or range between devices. Combining estimates from three or more devices, or trilateration, can then be used to compute a position estimate.
