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4G to 5G Migration/Evolution

If you just read all the 5G initial definition/requirement documents introduced in 5G Definition page. You may think "It is too good to be realized. It would be easy to say but almost impossible to implement." It would to true that we cannot realize all those requirement overnight in a single step. But as you look back the history of wireless communication (actually any technology), most of new technology start from what we have now and gradually evolve piece by piece and eventually realize what we thought would be impossible.

5G would be realized in the similar fashion even though many of 5G document say '5G should take drastically different evolution path from the one we saw before'. We are already seeing some of the features regarded as very advanced feature in current technology (4G) but will become a kind of basic features in 5G. I think following illustration gives us pretty good idea of the evolution path. If you are interested in 5G technical details, but don't know what to do because there is no established standard/specification, following current 3GPP specification along the eveolution path can be a good starting point.

Following figure is from SK Telecom 5G WhitePaper (Strongly recommeded to read the full document).  

Following is from the white paper : 4G  Americas' recommendation on 5G Requirements and Solution. Again, read the full document first and use this table to refresh your memory as needed.

Main Study Topcis in Rel 13

Refer to 3GPP Evolution of LTE in Release 13 for official introduction. Also I found pretty good introduction from YouTube posted by Erricson : Tech Talk shows benefits of LTE Release 13

Following is my version of introduction.

< LTE in unlicensed spectrum >

Even without specification, this area has been discussed for pretty long time and some chipset vendors are already at the stage of testing for several month now (Apr 2015).  

This is a special kind of Carrier Aggregation and the basic idea is to use the licensed LTE spectrum as a PCC and use unlicensed spectrum as SCC. The most common unlicensed spectrum being used this purpose as of now is WLAN spectrum in 5 Ghz, but theoretically we can extend it to any spectrum.

Refer to RP-150055 for further details.

< Carrier Aggregation enhancements >

As of now (Rel 12), the maximum number of carrier we can aggregate is 5. The main items for this activity is to extend the number of aggregated carrier up to 32. There has already been a demo achieving 9 CC CA on Mar 31, 2015.

The network operator KT and mobile manufacturer SamSung did the demo for TDD 9 CC CA (Netmanias Interview with KT at MWC 2015: KT's demonstrations of LTE TDD (9-carrier CA, LTE-UL/DL CA and triple mode femto)

Refer to RP-142286 for details.

< LTE enhancements for Machine-Type Communications (MTC) >

Main objective for this activity is to implement a low throughput device at a very low cost. See MTC page for my summary and see RP-141865 for further details.

I think it is highly likely that a lot of technology developed in this area would be adopted by 5G as well.

< Enhancements for D2D >

D2D has been investigated since Rel 12 and basic concept is summarized in my D2D/Prosec and D2D/Radio Protocol page. This objective of this activity is to make some enhancement to the existing topics.

Refer to RP-142311 for the details.

< Elevation Beamforming / Full-Dimension MIMO >

Main objective in this activity is to define the technology to increase the number of downlink Antenna (max 64) and to arrange those antenna in 2 dimensional grid.

I think the technology developed here would likely to be adopted in 5G. Refer to RP-141831 for the details.

< Enhanced multi-user transmission techniques >

In this activie, it will be investigate to realize techniquest to achieve MU MIMO which is tolerent to intra cell interference and can work even when the orthogonality is not guaranteed.

I think this technique in combination with FD-MIMO will be very important technical component in 5G. Refer to RP-142315 for details.

< Indoor positioning >

Refer to RP-141102 for details.

< Single-cell Point-to-Multipoint (SC-PTM) >

Refer to RP-142205 for details.

Main Study Topcis in Rel 14

No official 3GPP document about 5G in Release 14 is available for now, but following is a list of maijor features of Rel 14 presented by Qualcomm in RAN 5 Meeting ( Sep 2015).

• 5G Requirement Study at RAN Level
• 5G Design Study Item : structure of air interface to cover multiple areas
• mobile broadband
• internet of everything (IOE)
• mission critical
• high-freuquency range up to 100Ghz
• Parallel study on high-frequency channel model ( > 6 Ghz)
• LTE evolution to continue (Refer to 3GPP Rel 14 Features)

Main Study Topcis in Rel 15

No official 3GPP document about 5G in Release 15 is available for now, but following is a list of maijor features of Rel 15 presented by Qualcomm in RAN 5 Meeting ( Sep 2015).

• First Phase of 5G : mobile broadband
• licensed & unlicensed
• FDD & TDD
• at least < 6Ghz bands
• scalability up to < 40 Ghz bands
• wideband up to < 300 Mhz
• new subframe design
• shorter TTI/RTT
• LTE anchor (dual connectivity)
• forward compatibility hooks
• 5G study continues in parallel
• mmW, IOE, mission critical, standalone operation (no LTE Anchor)
• LTE evolution to continue

Main Study Topcis in Rel 16

No official 3GPP document about 5G in Release 16 is available for now, but following is a list of maijor features of Rel 16 presented by Qualcomm in RAN 5 Meeting ( Sep 2015).

• Second Phase of 5G : all other 5G components
• 5G Mobile Broadband Standalone Operations
• Mission Critical
• mmWave & high frequency range
• LTE evolution to continue
• Final Submission to ITU for IMT-2020