New waves of WiFi are here

Recent  advances  promise faster networks  at home -- and SIM-based  hotspots everywhere
By Anand Parthasarathy
Bangalore, November 11 2019:The 'connected'  TV was the tipping point:  suddenly lakhs of households in India saw sense in  installing a home WiFi network: It provided economic Internet access for   multiple  mobile phones; it fuelled PC and laptop -- and it 'smartened' the television set,  enabling  the family to enjoy at a time of  its choosing,  hundreds of new movies and serials   from  Net-based providers like Hotstar, Netflix,Amazon and the like. The purchase of a home  WiFi router has passed that very Indian test of 'paisa vasool' -- good value for money.
The router industry  is  gearing to  satisfy this burgeoning demand, with  better, faster, more reliable  networks. I have been trying out two routers  from a leading supplier -- D-Link --   that  cater to two  interesting use cases.
SIM-based  routers: Use-anywhere  Internet
Home routers traditionally need the owner to insert into the  WLAN port,  a cable with a  data connection , offered by a broadband provider.  But what if you are on the move  and can't tap into your home  cable? The D-Link DWR-921 4G LTE Router  offers a second option ( you can  still use the WLAN if you want). It comes with a slot for a mobile phone SIM. And since all mobile services these days offer a data plan,  the router will tap this to  connect to the Internet.
The beauty of this solution is that unlike  using a SIM in a phone, putting it into the router, allows  multiple users to benefit -- you can even use  any of the four ethernet ports  to connect  PCs, laptops etc.
The router  works  with all 3G and 4 G LTE  SIMs, which means you can in theory,  get  download speeds of  100  MBPS   ( and half that in upload).  The DWR-921  is a single band   system, ie it transmits in the  2.4 GHz band and not in the 5 GHz band. It is a small price to pay for offering 2 modes of  broadband access: through a WLAN cable and through a phone SIM.
In fact even in a home use case, one might prefer to buy a SIM with a good data plan as an alternative to  subscribing to cable data.  Just 300 grams, the router  can be easily carried while travelling. It will liberate you from dependence on hotel or public WiFi which is rarely secure.  The MRP is Rs 10,148    but I notice that on e-comm sites like Amazon, the discount is nearly 50%.
Mu-MIMO is way to go
The conventional Single User   router technology  has a small drawback:  It can serve one customer at a time. If you are working on your laptop and your child is streaming a movie at the same time -- there will definitely be a loss of speed at your end.  Mu-MIMO or Mult User - Multiple-In-Multiple-Out routers like the D-Link DIR 841, AC1200 , break up the bandwidth into separate streams so that each shares  the connection evenly, no matter which node is sucking up how much. 
MU-MIMO routers  only work with the newer 802.11 ac wireless protocol  which provides  download speeds of  between 300 and 800 MBPS . There is a small caveat: The host devices like your laptop or phone  should be able to decode  MU-MIMO,  otherwise you won't enjoy the full advantage.  The DIR 841  is marked  Rs 3540, but  I saw significant markdowns at Flipkart. I would still go for it even though I don't have any  devices that can do justice -- yet. Call it future proofing.