Are their ways of improving wifi coverage and speed without using a wired LAN and multiple access points ?

Technology Perspective:
Wifi was designed to be great at sharing an internet connection between multiple, never as a substitute for Wired LAN at exchanging data between two devices in the same network. With xDSL speeds in India evolving slowly from 2mbps to about 16 mbps (2 MB/s), Wifi speeds were just sufficient enough for sharing an internet connection and as a bridge to wired fixed like Broadband.

With FTTx (Fiber Optics), the broadband speeds have jumped to 20mbps, 30 mbps, 60 mbps, 100 mbps and even 1 Gbps in some cities. This has suddenly created 5-50 times speed jump for internet access speeds. Wifi simply could not evolve that fast [Its typically 3X with each technology (a, b, g, n, ac) change]. So today Wifi speed is a bottleneck for getting high speed broadband access from any *single* device.


Requirement:

In APR, Broadband speeds have reached 100 mbps and in many other parts on India 1 Gbps broadband is being offered uin under Rs. 3000 per month. So WAN to LAN connectivity max speed is 120 mbps to 1 Gbps today. If any wifi device wants to tap into this speed the wifi link must also support a throughput of at at-least 100 mbps today and possibly 1 Gbps or more in the near future,

Limitation:

We have not seem any router and client combination that can do such speeds on wireless network. So at this point of time, trying to bridge the Wireless wired speed gap is an exercise in vain. Wifi started (with 11 mbps and 54 mbps speed) as a good technology for sharing Internet connection (mostly narrow-band or early xDSL broadband implementations) between multiple device and the home. It never was great at sharing lot of data quickly between two devices, just simple to use. But Today Wireline Broadband (primarily due to FTTx) has far outpaced even the fastest throughput that Wifi can offer and therefore it is no longer by itself a great choice for sharing a high speed wireline internet connection. 

Temporary Solutions:

Some options do exist on how to improve wifi coverage and speed and are reported to work well sometimes doubling the speeds. They are:

1. Check if your router's antenna can be replaced by High gain omni-directional antennas (5dB, 8 dB, or higher) especially if your devices are placed at longer distance from router. Make sure your router supports this and then buy only compatible model. High gain antennas work surely for outdoor Wifi at great lengths if you have line of sight between device and AP/Router
2. Use of directional antenna (incl. Yagi antenna) to replace your router's antenna if signal is weak in on edirection
3. Use hacks like these below:
1. https://www.youtube.com/watch?v=ED5vl6IYto0
2. https://www.youtube.com/watch?v=lG5cEik2ABY 
3. https://www.youtube.com/watch?v=mYr0PCbLSHk
4. Use a Wifi Repeater or range extender. The repeater has to be placed somewhere we you get a good signal rather than somewhere where your signal strength is poor, so that it can extend the good signal to the area where it is poor. They come in Rs. 1000-3000 range and many Wireless router/AP can also be configured as range extenders. Please however note that the range extender will half the speed available at the place point point. 

But the MOST IMPORTANT TRICKs that will do 90% of the job will be to

• Try to put your router/AP in a central location or closer to where high speed access happens AFAP. It is not the default location provided by builder therefore, unfortunately needs cabling modifications
• Try to mount your router/AP near the ceiling with antennas facing downwards rather than conventional deployment where we place router on a raised platform on the floor. This is useful as devices face less attenuation from household objects in top to down direction and many clients will get LOS to router/AP. But again this needs wiring changes

Long term (possibly Permanent) solution:
Refer this Q&A (http://home-network-aprc-p3.blogspot.in/2015/10/what-is-future-of-wifi-technology-and.html)


- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee