A wireless repeater (also called wireless range extender or wifi extender) is a device that takes an existing signal from a

wireless router A wireless router is a device that performs the functions of a router and also includes the functions of a wireless access point. It is used to provide access to the Internet or a private computer network. Depending on the manufacturer and mode ...

wireless access point In computer networking, a wireless access point (WAP), or more generally just access point (AP), is a networking hardware device that allows other Wi-Fi devices to connect to a wired network. As a standalone device, the AP may have a wired ...

and rebroadcasts it to create a second network. When two or more hosts have to be connected with one another over the IEEE 802.11 protocol and the distance is too long for a direct connection to be established, a wireless repeater is used to bridge the gap. It can be a specialized stand-alone

computer networking device Networking hardware, also known as network equipment or computer networking devices, are electronic devices which are required for communication and interaction between devices on a computer network. Specifically, they mediate data transmission in ...

. Also, some wireless network interface controllers (WNIC)s optionally support operating in such a mode. Those outside of the primary network will be able to connect through the new "repeated" network. However, as far as the original router or access point is concerned, only the repeater MAC is connected, making it necessary to enable safety features on the wireless repeater. Wireless repeaters are commonly used to improve signal range and strength within homes and small offices.

Uses

*When there is no

wireless hotspot A hotspot is a physical location where people can obtain Internet access, typically using Wi-Fi technology, via a wireless local-area network (WLAN) using a router connected to an Internet service provider. Public hotspots may be created by ...

in an area *In an area with much interference. *Interference can be caused by many environmental factors such as

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...

s (such as from a microwave oven), metal appliances or metallic coating or an impeded

line of sight The line of sight, also known as visual axis or sightline (also sight line), is an imaginary line between a viewer/observer/ spectator's eye(s) and a subject of interest, or their relative direction. The subject may be any definable object taken ...

. *When the distance between the computer and the wireless access point or wireless router is too great for the internal

wireless network interface card A wireless network interface controller (WNIC) is a network interface controller which connects to a wireless network, such as Wi-Fi or Bluetooth, rather than a wired network, such as a Token Ring or Ethernet. A WNIC, just like other NICs, wor ...

to receive the wireless signal. *When networking in an environment with interference and multiple computers, networks or hubs

Drawbacks

Since only one wireless device can transmit at once, wireless transmissions are doubled (router to the repeater and then repeater to the client versus just router to the client), and so: * Wireless throughput is reduced by at least 50%. * Wireless interference (e.g., with other networks on the same channel) is at least doubled. * Potentially opens another security attack vector. Older devices don't always support WPA2, so while the original network might be secure, the secondary one is potentially open. Furthermore, the quality of the connection to an extender is generally worse than if connected to the host access point.

Connectivity

Some wireless range extending devices connect via a USB port. These USB adapters add Wi-Fi capability to desktop PCs and other devices that have standard USB ports. USB supports not only the data transfers required for networking, but it also supplies a power source so that these adapters do not require electrical plugs. Some wireless repeaters have a power outlet. With those repeaters, you can still use your wall socket while using the repeater. Some wifi range extenders have an

ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...

port to also provide a wired connection.

Compatibility

There are wireless range extending devices that conform to all

802.11 IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer com ...

protocols. Most 802.11 compliant devices are backward compatible. However,

802.11ac IEEE 802.11ac-2013 or 802.11ac is a wireless networking standard in the IEEE 802.11 set of protocols (which is part of the Wi-Fi networking family), providing high-throughput wireless local area networks (WLANs) on the 5 GHz band. The stand ...

runs at 5 GHz and requires an access point capable of 5 GHz operation. 802.11ac is the most recent and third-generation Wi-Fi standard for wireless home networking. 802.11ac equipment is backward compatible with 802.11n, 802.11g, or 802.11b equipment. An older range extender will not be able to repeat the signal of a newer generation router. Security encryption compatibility also matters and must be at the same level of compatibility for the signal to be extended. For example, an older range extender that supports WEP and WPA will not be able to boost a WPA2-encrypted signal from a router.

Alternatives

Most wireless repeaters (or range extenders) are purpose-built, but certain wireless routers can be flashed with custom firmware such as

DD-WRT DD-WRT is Linux-based firmware for wireless routers and access points. Originally designed for the Linksys WRT54G series, it now runs on a wide variety of models. DD-WRT is one of a handful of third-party firmware projects designed to replace ...

to give them a 'range extender' option. A better option for extending wireless coverage is to configure a secondary box as a

, with a wired connection between a LAN port on this secondary box and a LAN port on the primary box (a router). If

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...

wiring is not an option, an alternative is powerline networking. Wireless extender kits consisting of a powerline adapter module (connected to the wireless router) and a wireless extender module (integrated powerline networking and wireless access point) are available.

References