Uncertainty abounds concerning the actual performance of Wi-Fi at 5 and 60 GHz, as maximum theoretical data rates are typically unattainable in real-world environments. A great deal of complexity exists due to the various technical factors involved and the many different Wi-Fi transmission environments. In the white paper “Wi-Fi Data Rates, Channels and Capacity,” Qorvo discusses some of the factors that affect Wi-Fi performance and attempts to uncover the actual performance that consumers can expect.
The white paper provides a table that lists theoretical data rates of the different IEEE 802.11 standards. However, those maximum theoretical data rates can only be achieved in the lab under carefully controlled conditions, according to the document. Typical data rates depend on a number of factors, such as signal degradation with distance, modulation rate and forward error correction coding, bandwidth, and several others. The white paper then compares theoretical and advertised data rates with typical data rates, illustrating the differences between them.
Another topic discussed is the actual throughput per user, which depends on real-world transmission rates and local conditions. Factors to keep in mind include user activity level and distances to the access point, as well as average packet size on the link. Additional factors are the number of users per access point, along with the number of access points and clients on the same channel and within interference range.
Channels and capacity are then examined. Understanding the true capacity of Wi-Fi in a given situation requires taking into account the width of the Wi-Fi channel in use, the number of channels available, and the number of channels in use by other Wi-Fi devices.
The white paper then points out that the IEEE 802.11ax standard promises to deliver a fourfold increase in capacity relative to IEEE 802.11ac. Some of the aspects that will enable this performance to be achieved are detailed. Another major new feature is the provision of a flexible means to allocate channel capacity to specific clients for multi-user transmissions.
Qorvo Inc., 7628 Thorndike Rd., Greensboro, NC 27409; (336) 664-1233
