Cloud 4G 2/26/2019 | 4:31:07 PM
5G is a weaving of spectra and technologies What makes 5G more difficult to understand (swallow) is that unlike previous generations, it depends far more on a blending of multiple bands with multiple arrangements of technology that are applied to achieve multiple service profiles.  If you ask anyone what 5G is you get as many opinions as there are operators and the departments within them that are working on the broadened envelope of applications that depend on spectra and capital resources to leverage their unique position in marketshare.   


In 2G, 3G, 4G, operators had varying portfolios of spectra and capital but the motivating application was mobile phone service. 


Massive MIMO fits as part, but only part, of 5G.  It tends to have a higher impact when used in frequencies above about 2 GHz.  The higher up in frequency, as a general rule, the smaller the individual antenna elements and closer they can be packed within the arrays.  Signals also travel in more of a straight line with less interference because they can be more cleanly beamed despite the tendency to bounce more off of solid objects.  That makes for good use of Massive MIMO in 2.5-2.6GHz Band 41 help by Sprint.  However, that alone cannot fill in the needs for the building of competitive 5G networks.


5G is no single band or single prescription of multiple bands.  Rather, it is a long in development tiered network access system combined with network and user devices that implement multiple bands and multiple carrier band path radios and the supporting signal processing. M-MIMO can't defy laws of physics to bend high-frequency signals around hills and buildings.  M-MIMO works best in combination with massively distributed, multiple-tiered band networks that use large numbers of smallcells.  


Take a look back at Sprint's 'Network Vision' presentations: they look eerily similar to those of Ericsson, Nokia, Huawei for how to build a 5G network: use lower bands for coverage, mid-band for a combo of coverage and bandwidth, and high-band for xHaul and Gigabit wireless.  This is what is now proposed by New T-Mobile except that it takes what has been a futile effort by Sprint to use a preponderance of mid-band using M-MIMO and every other thing to make use of T-Mobiles broadband allocations (10x10 MHz or greater) to fulfill the coverage layer at low deployment cost and the greater simplicity, rapidity and low service cost.

Massive MIMO has been part of 4G-Advanced the makes better commercial sense as part of the expanded universe of 5G spectra and applications.  It has not been a game changer for Sprint.  It will be a part of what helps New T-Mobile change the competitive mix as one of the network layers.  The deployment and applications environment changes due to the combination more than the individual piece of technology. 
e2mbcorp 2/19/2019 | 12:10:15 PM
No Antenna Can Solve Packet Efficiency Great story Mike, but as always, if we keep the discussion around the physical layer and bandwidth speed, then we are not focusing on the root cause of the problem.  This is because no amount of bandwidth speed can solve a problem in switch architecture.  The root of the problem is the collision detection mechanism.  5G's access channel uses ALOHA for that purpose, which results in approximately 50% packet efficiency at the MAC layer.  Fixing this bottleneck will have an automatic antenna improvement when layer 1 does not need to contend with the bottleneck at layer 2.  Or we can just keep throwing bandwidth at a problem it can't solve, which is what we've been doing for the last 30 years so I hope nobody is expecting a different result.
Mike Dano 2/19/2019 | 11:08:08 AM
Re: MIMO Functionality Wow what a nice comment. Thank you!
jamiekimble 2/19/2019 | 10:58:35 AM
MIMO Functionality Mike, another well written story that is fact based.  Thanks for publishing this article.
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