2. Ultra-High Radio Speed ⇒ Enormous traffic converging into the Core ⇒ Distributed 5G Core
In 5G era, radio IP capacity will become as large as 20Gbps per sector (mobile speeds up to 20Gbps), and ultra-large content traffic (e.g. UHD Video Streaming, Augmented Reality (AR), Virtual Reality (VR)) will travel across the faster radio access network. All mobile traffic have to travel via packet core network (i.e. PGW in case of 4G). Today, most countries have only a few sites with PGWs across their nations (e.g. In Korea, all PGWs are at two sites in Seoul only).
If the current architecture is kept, massive backhaul between BBU Pools located across the country and packet core in a few centralized sites is inevitable, and substantial backhaul investment has to be made as well. For instance, let's say there are 10,000 5G cell sites nationwide, each with 3 sectors. Backhaul capacity required is 600Tbps (20Gbps/sector x 3-sector x 10,000 sites). Of course, 5G core in centralized sites should have ultra high processing capacity as well.
Figure 3. Backhaul explosion due to the converging into packet core
Because of the foregoing circumstances, Korean and global operators prefer 5G solutions that involve distribution of 5G core nodes close to cell sites. If 5G core nodes are distributed closer to cell sites, content servers (or caching servers) can be placed on the rack right next to the distributed 5G core. And this can help significantly reduce backhaul traffic by having mobile devices download content immediately from the content server without having to pass the backhaul to reach 5G core. According to a test conducted by SK Telecom, backhaul traffic was decreased in deed by over 30%.
Both KT and SK Telecom decided to distribute their packet core to local sites across the country in the coming 5G era. 5G Core (Data Plane), New BBU and Applications will run on virtualized servers at the local cloud RAN sites.
Figure 4. Distributed 5G Core
3. Ultra-low latency ⇒ Distributed 5G Core
Many agree that massive IoT and mission-critical IoT are the biggest difference between 4G and 5G. Mission-critical IoT (Ultra-reliable and low latency communications) applications include remote controlled machine, autonomous driving (self-driving), etc. These types of ultra-real-time services require radio latency of less than 1ms, and end-to-end latency of less than a few ms. The best way to achieve minimal end-to-end latency in terms of network architecture would be to eliminate backhaul delay by distributing 5G core closest to mobile devices, and placing application servers right next to it. Distribution of 5G core that we have just discussed above will naturally give us the same effect.
Key elements of the 5G mobile network architecture presented by the Korean big 3 can be summarized as distribution of 5G core, and introduction of new packet-based fronthaul.
See Also
E2E Network Slicing - Key 5G technology : What is it? Why do we need it? How do we implement it?
5G network as envisioned by KT - Analysis of KT's 5G network architecture
This is perfectly captured. So true. Though most of them know some one have not put it for publishing. It is nice that Netmanias have done it.
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Very well written and excellent article highlighting the issue of back-haul explosion. MEC will surely free the backhaul from Operator's Intranet, but the 5th generation of traffic, which would be Internet of Many-Many-Things, would also mean that other parties need to run their applications on virtualised servers. For example, even if the Operator manages to terminate the 'Smart Power' traffic at RAN, it still needs to be routed to a remote server located in the grid's premises, unless the utility company decides to go cloud.
This boils down to a very fundamental question - what would motivate others to match the fast moving wireless evolution? For a utility company, it would bring efficiency in energy distribution, but does such incentive exists for all? Or, will the telco define a common cloud architecture to facilitate every partner’s application? Much to think and much more to be standardised in this fast developing space…..
Good summary
Have to agree, well written article
Fronthaul and backhaul explosions requirements for 5g makes current 4g just a small begining of a larger global connected world....
Very well explained , it's a delight to read such a document . I always love reading Netmania's stuff as these guys are so good in presenting and explaining the things and most importantly are doing a Great and good job of spreading knowledge with timely latest updates and in an authentic way.
Really Appreciate it !!
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Very Interesting and updated blog on 5G networks architecture. Thank you for sharing.
Migration from current networks infrastructures to 5G needs to be carefully studied and detail the migration plans in taking into consideration minimization of major hardware replacement and impacting network serviceability.
Nice Article!!! Very Much informative for engineers who want to excell in Telecommunciation field!!!
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Nice ! Successfull commercial implementation hurdle will hinge on fronthaul and backhaul advancement and if the C-RAN is going to be distributed or centralized. Distributed C-RAN with NFV will be the way forward.
Excellent article! This explosion will certainly be more critical in wide area countries like Brazil!
Thanks for sharing!
Really Most of my basic concepts cleared by Netmanias .. Thanks for that . Really wonderful content.
Great document indeed. Can you please show the calculations as to how you arrived at the following two statements? (1) "Each RRH has two antennas (2T2R) and has LTE channel bandwidth (BW) of 20MHz. So, the capacity of CPRI interface is 2.45Gbps.", and (2) "For example, if BW is 20MHz and an RRH has 16 antennas, then 19.66Gbps of CPRI capacity is required between BBU and the RRH."?
Very good topic. Really helps.
Great job Netmanias!! The site to visit for Next-Gen mobile technology. Keep up the great work.