
The need for wartime technology in World War II inspired the invention of wireless communications. Actress Hedy Lamarr and composer George Antheil invented a technological system that allowed radio waves to jump onto different frequencies, blocking enemy ships of the US Navy from jamming torpedo guidance signals. This frequency hopping technique is a staple in modern wireless technologies that are described in ANSI/USEMCSC C63.27 2021: American National Standard for Evaluation of Wireless Coexistence.
The ANSI/USEMCSC C63.27 2021 Standard for Wireless Coexistence
ANSI/USEMCSC C63.27 2021 provides methods for assessing the radio-frequency (RF) wireless coexistence of equipment. Wireless coexistence is the ability of a device to properly function in an electromagnetic environment with other unrelated, noisy signals. ANSI/USEMCSC C63.27 2021 specifies key performance indicators (KPIs) used to evaluate the ability of the equipment under test (EUT) to coexist with other equipment in its intended operational environment. The purpose of the standard is to provide guidance, such as evaluation procedures and test methods, for assessing the ability of the EUT to successfully maintain its functional wireless performance (FWP) in the presence of unintended signals.
Wireless Coexistence Testing in ANSI/USEMCSC C63.27 2021
A coexistence evaluation assesses the ability of the EUT to perform its intended operation in the electromagnetic (EM) environments in which it will be used. The evaluation focuses on the functions that use the wireless capability of the EUT. The test plan examines the intended EM environment, FWP of the EUT, evaluation tier to assess the FWP, intended signal, and unintended signals.
Additionally, ANSI/USEMCSC C63.27 2021 uses KPIs like latency, jitter, throughput, error vector magnitude (EVM), non-acknowledgement requests, lost packets, number of retransmissions, and time to complete requests to measure uncertainty and change in performance.
Coexistence testing is performed:
- To develop user guidance to achieve a reliable operation when communicating between EUT nodes
- To determine the potential for successful operation of the FWP with regard to coexistence
- To estimate the user experience
- To diagnose complaints and failure reports and qualify modifications that remediate the product performance
- To identify the intended environment parameters at which the EUT fails to coexist

What Is a Wireless Network?
A wireless network allows devices to stay connected without using cables and instead utilizing Radio Frequency (RF) connections between nodes in the network. Devices thereby use radio communications to send data between on another. Wireless networks are popular for homes, businesses, and telecommunications networks. There are four main types of wireless networks:
- Wireless Local Area Network (LAN): Connects within a within a localized area that usually share a centralized Internet connection, such as an office, home, or limited outdoor area. It is a collection of devices connected together in one physical location.
- Wireless Wide Area Network (WAN): Covers large areas, such as towns, cities, and around the globe via a WAN provider.
- Wireless Metropolitan Area Networks (MAN): Provides Internet access outside office and home networks, usually regional. It connects multiple LANs across a large area but is smaller than a WAN.
- Wireless Personal Area Network (PAN): Interconnects devices in a short span, generally within a person’s reach, such as to a wireless mouse, computer, or keyboard.
What Is the Difference Between Wireless and Wi-Fi?
Both Wireless and Wi-Fi connect to Internet, but they describe two entirely different ways of doing so. In a wireless setup, the device sends and receives data through the nearest cellular tower owned by the user’s mobile phone company. In a Wi-Fi setup, a device connects to a router or access point that transmits communications to your device via a broadband modem. Simply put, here is the biggest difference:
- A wireless connection utilizes a cellular network and allows you to use the Internet almost anywhere. It is primarily used by mobile phones (but it is possible to utilize a wireless connection with a computer after installing the required hardware).
- A Wi-Fi connection requires you to install hardware in your home or use your computer within range of a router or access point to which you have access.
ANSI/USEMCSC C63.27 2021: American National Standard for Evaluation of Wireless Coexistence is available on the ANSI Webstore.
