A wireless range extender takes an existing signal from a wireless router or wireless access point 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.
Transmission speed for clients connecting through a range extender is not usually equivalent to direct service from the base station, and there is an increase in latency for each hop. Range extenders are more effective for clients that can access a weak signal than for those that cannot access a signal at all.
There are wireless range extending devices that conform to all 802.11 protocols. Most 802.11 compliant devices are backwards compatible. However, 802.11ac 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 which supports WEP and WPA will not be able to boost a WPA2-encrypted signal from a router.
There are several vendors whith inexpensive products on the market. We recomend the NETGEAR:
Ideal for extending WiFi to devices like the iPhone 6, Samsung Galaxy S5, and Samsung Galaxy Tab 3;
WPS button for auto-setup. See demo video on Amazon product page
Ideal for extending WiFi to Echo/Alexa devices, WeMo & TP-Link Smart Plugs, TP-Link Smart Bulbs, the iPhone 7, Samsung Galaxy S7, iPad 4, PlayStation 4 and more;
Easy setup and flexible placement allows movement of the range extender to any outlet after initial setup