One of the interesting features of 5G is Ultra-Reliability and Low-Latency Communication or URLLC. It has been enhanced as part of 3GPP Release-16. A summary of the changes in eURLLC can be seen in the picture above.
This ATIS webinar that I blogged about last week covered this topic as well. For example L1/L2 changes have been summarised nicely in this Qualcomm slide above while the slide from Intel speaker below looks at redundant transmission and session continuity.
Redundant transmission in the user plane is an extremely useful feature, especially if the packets are mission critical and have to reach from the source to their destination in a guaranteed time / reliability.
Dual connectivity will enable this redundant path when required to meet a guaranteed reliability.
Here is a short video from the training company Mpirical, explaining the the 5G eURLLC feature:
An expert panel brings you up-to-speed on the current state of 5G standardization. The webinar delivers a broad overview of 3GPP's work and introduces some of the key technology elements. It is suitable for people in technical roles and technical executives who want to understand the current state of 5G standardization.
In Release 16, 3GPP delivered important updates to 5G specifications to broaden their range of commercial applications and improve the efficiency of networks. 3GPP is now further enhancing 5G in Release 17 and starting to plan Release 18. This webinar provides an up-to-date view of the completed 3GPP Release 16 work with a particular focus on how the work is expanding capabilities of 5G and enhancing the technical performance of the mobile system. It also looks ahead to future 3GPP deliverables and their use cases.
The webinar features, Iain Sharp, Principal Technologist at ATIS (Moderator), Greg Schumacher, Global Standards at T-Mobile USA and 3GPP SA and SA1 Vice Chairman, Puneet Jain, Director of Technical Standards at Intel and 3GPP SA2 Chairman and Wanshi Chen, Senior Director, Technology at Qualcomm and 3GPP RAN1 Chairman
Many interesting topics have been covered including the updates on mMTC and URLLC.
There is also details about new features coming in 3GPP Release-17 and an early look at what 3GPP Release-18 might include, as can be seen in the picture above.
We have been meaning to make a tutorial on augmented reality (AR), virtual reality (VR), mixed reality (MR) and extended reality (XR) for a while but we have only managed to do it. Embedded below is video and slides for the tutorial and also a playlist of different use cases on XR from around the world.
If you are not familiar with the 5G Service Based Architecture (SBA) and 5G Core (5GC), best to check this earlier tutorial before going further. A lot of comments are generally around Wi-Fi instead of 5G being used for indoors and we completely agree. 3GPP 5G architecture is designed to cater for any access in addition to 5G access. We have explained it here and here. This guest post also nicely explains Network Convergence of Mobile, Broadband and Wi-Fi.
Private Networks have been around for a while and really took off after 4G was launched. This is due to the fact that the architecture was simplified due to the removal of CS core and also the advancements in silicon, storage, computation, etc. allowed creation of smaller and more efficient equipment that simplified private networks.
While private networks imply an isolated network for selected devices that are allowed to connect on to the network, Non-Public Networks are much broader in scope. Chief among them is the ability of certain devices to be capable of working on Private as well as Public Network or roaming between them.
I recently ran a workshop on 'Introduction to Private 4G & 5G Networks' with a well known Industry analyst Dean Bubley. One of the sections looked at the Network Architecture based on the 3GPP standards. This tutorial is a part of that particular section. Slides and video embedded below. There are also some interesting videos on YouTube that show how and why Private Networks are needed and some use cases. The playlist is embedded in the end.
It's been a while since I last wrote about IAB on this blog here. At that time 3GPP Release-16 was being discussed. Since then things have moved on. While Release-16 is being prepared for final release soon, Release-17 study and work items have just been agreed upon.
IAB is included as part of Rel-16 but there isn't a comprehensive document or presentation easily available to details all that it will contain. Similarly the enhancements for Release-17 are available only superficially. Qualcomm is well known for making some really excellent presentations available on 5G. One of their presentations from January (here) has some details on IAB (pg. 32 - 35). There was also an excellent presentation by Navid Abedini, Qualcomm from IEEE Sarnoff Symposium, 2019 which is embedded at the end.
In a 3GPP RAN#84 discussion document RP-191181, Samsung has provided a comprehensive summary of what is being done as part of Rel-16 and what did not make in that:
Rel-16 IAB aims at basic operations
Architecture and protocol design
IAB integration procedure
Routing, BAP and BH configuration
CP and UP data transmission via IAB
Topology support:
Spanning Tree (ST) and Directed acyclic graph (DAG)
Intra-Donor adaptation is prioritized
The following cannot be supported in Rel-16
Mobile IAB
Topology support: Mesh
Some functionalities in Rel-16 may not be completed due to time constrains e.g.
Topology adaptation between IAB donors
Mechanisms for efficient control signaling transmission
Ericsson also provides a good summary in RP-190971 regarding Release 16 IAB and Rel-17 enhancements:
IAB Rel-16 provide basic support for multi-hop and multi-path relaying.
The solution supports
QoS prioritization of traffic on the backhaul link
Flexible resource usage between access and backhaul
Topology adaptivity in case link failure
In Rel-17 it would be possible to further evolve the IAB solution targeting increased efficiency and support for new use cases
Meanwhile in the recently concluded RAN#86, AT&T provided a good detailed summary on what enhancements are required for IAB as part of Rel-17 in RP-192709
Duplexing enhancements
Multiplexing beyond TDM (FDM/SDM/multi-panel Tx/Rx) including multi-parent scenarios, case 6/7 timing alignment, power control/CLI optimizations
Topology enhancements
Mobile IAB: CP/UP split + Group mobility
Inter-CU topology adaptation
Mesh-connectivity between IAB nodes for local control/user plane routing
User plane enhancements
Multi-hop scheduling enhancement – exchange of benefit metric between IAB nodes to enable radio-aware multi-hop scheduling to improve throughput performance
Network Coding
Study benefits compared to duplication over redundant backhaul routes
We will have to wait and see what makes it into the enhancements and what don't. Meanwhile here is a video from Navid Abedini, Qualcomm from IEEE Sarnoff Symposium, 2019
3GPP TSG RAN#84 was held from June 3 – 6, 2019 at Newport Beach, California. Along with a lot of other interesting topics for discussion, one of the new ones for Release-17 was called NR-Lite (not 5G-lite). Here are some of the things that was being discussed for the Study item.
In RP-190831, Nokia proposed:
NR-Lite should address new use cases with IoT-type of requirements that cannot be met by eMTC and NB-IoT:
Higher data rate & reliability and lower latency than eMTC & NB-IoT
Lower cost/complexity and longer battery life than NR eMBB
Wider coverage than URLLC
Requirements and use cases –
Data rates up to 100 Mbps to support e.g. live video feed, visual production control, process automation
Latency of around [10-30] ms to support e.g. remote drone operation, cooperative farm machinery, time-critical sensing and feedback, remote vehicle operation
Module cost comparable to LTE
Coverage enhancement of [10-15]dB compared to URLLC
Battery life [2-4X] longer than eMBB
Enable single network to serve all uses in industrial environment
URLLC, MBB & positioning
The spider chart on the right shows the requirements for different categories of devices like NB-IoT, eMTC (LTE-M), NR-LITE, URLLC and eMBB.
The understanding in the industry is that over the next 5 years, a lot of 4G spectrum, in addition to 2G/3G spectrum, would have been re-farmed for 5G. By introducing NR-Lite, there would be no requirement to maintain multiple RATs. Also, NR-Lite can take advantage of 5G system architecture and features such as slicing, flow-based QoS, etc.
Qualcomm's views in RP-190844 were very similar to those of Nokia's. In their presentation, the existing 5G devices are billed as 'Premium 5G UEs' while NR-Lite devices are described as 'Low tier 5G UEs'. This category is sub-divided into Industrial sensors/video monitoring, Low-end wearables and Relaxed IoT.
The presentation provides more details on PDCCH Design, Co-existence of premium and Low Tier UEs, Peak Power and Battery Life Optimizations, Contention-Based UL for Small Data Transmission, Relaying for Wearable and Mesh for Relaxed IoT
Ericsson's presentation described NR-Lite for Industrial Sensors and Wearables in RP-191047. RP-191048 was submitted as New SID (Study Item Description) on NR-Lite for Industrial Sensors and Wearables. The SID provides the following details:
The usage scenarios that have been identified for 5G are enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and time critical machine-type communication (cMTC). In particular, mMTC and cMTC are associated with novel IoT use cases that are targeted in vertical industries. In the 3GPP study on “self-evaluation towards IMT-2020 submission” it was confirmed that NB IoT and LTE M fulfill the IMT-2020 requirements for mMTC and can be certified as 5G technologies. For cMTC support, URLLC was introduced in Release 15 for both LTE and NR, and NR URLLC is further enhanced in Release 16 within the enhanced URLLC (eURLLC) and Industrial IoT work items. One important objective of 5G is to enable connected industries. 5G connectivity can serve as catalyst for next wave of industrial transformation and digitalization, which improve flexibility, enhance productivity and efficiency, and improve operational safety. The transformed, digitalized, and connected industry is often referred to as Industry 4.0. Industrial sensors and actuators are prevalently used in many industries, already today. Vast varieties of sensors and actuators are also used in automotive, transport, power grid, logistics, and manufacturing industries. They are deployed for analytics, diagnostics, monitoring, asset tracking, process control, regulatory control, supervisory control, safety control, etc. It is desirable to connect these sensors and actuators to 5G networks. The massive industrial wireless sensor network (IWSN) use cases and requirements described in TR 22.804, TS 22.104 and TS 22.261 do include not only cMTC services with very high requirements, but also relatively low-end services with the requirement of small device form factors, and/or being completely wireless with a battery life of several years. The most low-end services could already be met by NB-IoT and LTE-M but there are, excluding URLLC, more high-end services that would be challenging. In summary, many industrial sensor requirements fall in-between the well-defined performance objectives which have driven the design of eMBB, URLLC, and mMTC. Thus, many of the industrial sensors have connectivity requirements that are not yet best served by the existing 3GPP NR technology components. Some of the aforementioned requirements of IWSN use cases are also applicable to other wide-area use cases, such as wearables. For example, smart watches or heath-monitoring wearables require small device form factors and wireless operation with weeks, months, or years of battery life, while not requiring the most demanding latency or data rates. IWSN and wearable use cases therefore can motivate the introduction of an NR-based solution. Moreover, there are other reasons why it is motivated to introduce a native NR solution for this use case:
It is desired to have a unified NR based solution.
An NR solution could provide better coexistence with NR URLLC, e.g., allowing TDD configurations with better URLLC performance than LTE.
An NR solution could provide more efficient coexistence with NR URLLC since the same numerology (e.g., SCS) can be adopted for the mMTC part and the URLLC part.
An NR solution addresses all IMT-2020 5G frequency bands, including higher bands and TDD bands (in FR1 and FR2).
The intention with this study item is to study a UE feature and parameter list with lower end capabilities, relative to Release 15 eMBB or URLLC NR, and identify the requirements which shall be fulfilled. E.g., requirements on UE battery life, latency, reliability, connection density, data rate, UE complexity and form factor, etc. If not available, new potential NR features for meeting these requirements should further be studied.
There were other description of the SID from Samsung, ZTE, etc. but I am not detailing them here. The main idea is to provide an insight for people who may be curious about this feature.
This year April Fools' Day wasn't as fun as the last one, even though it was on Monday. Many tech companies that make effort didn't make one this year. In fact Microsoft went even further and banned any public facing April Fools' pranks. Anyway, here are some of the jokes that I found interesting.
Parallel Wireless 7G Vision
This one was important for me as it features me (Yay!) and also enhanced my video editing skills. Grateful to CW (Cambridge Wireless) for being part of it too.
In short, the focus for the next few years will be do design a 7G logo that can explain the vision and connect with people. Did I mention 7GPPPPP?
"#7G Public Private Political Polling Partnership (7GPPPPP) with many different companies and organizations has also been formed to work on this vision."
The company says that the game is rolling out now to iOS and Android users globally today, and that it’ll remain on the app for the rest of the week. It also launched a standalone site to play the game if you don’t have the app.
Jabra Ear bud(dy)
World’s first shared headphone - engineered for shared music moments. The website says:
The headphones come with an ultra-light headband that extends seamlessly to accommodate the perfect fit for every pair of buddies, so you’ll never have to enjoy another music moment alone. The Jabra Earbud(dy)™ comes with a unique Buddy mode that promises a shared music experience that is tailored to suit each person’s preferences. Fans of voice command will be thrilled to know that with just one touch, the Jabra Earbud(dy)™ can connect to dual voice assistant.
T-Mobile Phone BoothE
T-Mobile USA and their CEO John Legere never disappoints. They always come up with something interesting. Here is a video of the prank
T-Mobile is again fighting one of the so-called pain points of the wireless industry with the launch of the Phone BoothE, a completely sound-proof and high-tech phone booth that lets T-Mobile customers escape from noisy areas to make their phone calls. Inside the Phone BoothE you can charge your devices, connect to a smart screen called "Magenta Pages" to mirror your smartphone display, and adjust the lighting to take great selfies. In regards to the name, T-Mobile is taking a shot at AT&T's misleading 5GE label: "The Phone BoothE is an evolution towards the new world of mobility. Like many in the tech and wireless industry today, we decided that by adding an "E" to the name, you would know it's a real technology evolution." Although this is an April Fools' Day joke, T-Mobile has actually built the Phone BoothE and deployed them in select locations around New York City, Seattle, and Washington, DC, where anyone will be able to use them. The company on Monday also revealed the T-Mobile Phone BoothE Mobile EditionE, which is more in line with a straightforward April Fools' Day hoax, as it's "literally a magenta cardboard box with a hole in it."
While the actual site disappeared after April 1, the archived version can be seen here.
The Nokia 9 PureView has plenty of cameras on its back, but did you know that the black sensor isn’t a 3D ToF camera but rather an X-Ray sensor? Can be unlocked with the new Nokia X-Ray app in Play Store
"Digi-U" from Ericsson Digital
We announce a new innovation from our @EricssonDigital team - a Digi-ize yourself app called: "Digi-U". This app is available for download to your smart phone and within 10 minutes you will have transformed yourself into a mini-me hologram.
Worlds First Fully Virtualized AMPS (vAMPS) to enable Modernization and Cost Savings Parallel Wireless vAMPS is compatible with: Total Access Communications Systems (TACS) in the U.K.; Nordic Mobile Telephone (NMT) System in Scandinavia; C450 in Germany; and NTT System in Japan, among others, and will allow global operators to modernize their 1G infrastructure. The 1G vAMPS solution is also software upgradable to vD-AMPS, for operators who wish to follow that path.
Truphone foldable SIM (F-SIM) for Foldable Smartphones
F-SIM – the foldable SIM – designed especially for the new foldable smartphones and tablets demonstrated at this February’s MWC Barcelona, including Huawei’s Mate X and Samsung’s Galaxy Fold. Widely tipped as the next generation in SIM technology, the foldable SIM works on minute hinges that allow it to fold smaller than any previous SIM form factor. Made specifically for foldable phones and other devices, Truphone’s latest innovation fulfils on its broader brand promise to engineer better connections between things, people and business—anywhere in the world. The F-SIM comes in ‘steel grey’ and, for only £5 more, ‘hot pink’. Pricing structures vary depending on data, storage, roaming charges and device model.
Google Screen Cleaner in the Files app
Mother of All USB-C Hubs for Apple Macbook - HyperDrive Ultimate Ultimate Hub
Many regular readers of this blog are aware that back in 2014 I wrote a post looking critically at LTE-Broadcast business case and suggested a few approaches to make it a success. Back in those days, 2014 was being billed as the year of LTE-Broadcast or eMBMS (see here and here for example). I was just cautioning people against jumping on the LTE-B bandwagon.
thirty-nine operators are known to have been investing in eMBMS demonstrations, trials, deployments or launches
five operators have now deployed eMBMS or launched some sort of commercial service using eMBMS
Its good to see some operators now getting ready to deploy eMBMS for broadcast TV scenarios. eMBMS will also be used in Mission Critical Communications for the features described here.
In a recent news from the Australian operator Telstra:
Telstra is now streaming live sports content to a massive base of around 1.2 million devices each weekend and sports fans consume 37 million minutes of live content over our apps on any given weekend. This increase brings new challenges to the way traffic on our mobile network is managed. Even though a large group of people might be streaming the same real-time content at the same time, we still need to ensure a high quality streaming experience for our customers. This challenge makes our sporting apps a prime use case for LTE-Broadcast (LTE-B). Earlier this year, we announced we would be turning on LTE-B functionality on the AFL Live Official app for Telstra customers with Samsung Galaxy S8 and Galaxy S9 devices. Following extensive testing, Telstra is the only operator in Australia – and one of the first in the world – to deploy LTE-B into its mobile network. At a live demonstration in Sydney, over 100 Samsung Galaxy S8 and Galaxy S9 devices were on display showing simultaneous high definition content from the AFL Live Official app using LTE-B.
Its interesting to note here that the broadcast functionality (and probably intelligence) is built into the app.
According to another Telstra news item (emphasis mine): The use of LTE-Broadcast technology changes the underlying efficiency of live video delivery as each cell can now support an unlimited number of users watching the same content with improved overall quality. To date though, LTE-B technology has required that a dedicated part of each cell’s capacity be set aside for broadcasting. This had made the LTE-B business case harder to prove in for lower streaming demand rates. This has now changed as Telstra and our partners have enabled the world’s first implementation of the Multicast Operation on Demand (MooD) feature whereby cells in the network only need to configure for LTE-B when there are multiple users watching the same content. This combined with the Service Continuity feature allows mobile users to move around the network seamlessly between cells configured for LTE-B and those which are not. Earlier this year we announced our intention to enable LTE-Broadcast (LTE-B) across our entire mobile network in 2018. With MooD and service continuity we are one step closer to that goal as we head into another year of major growth in sporting content demand. Supported by technology partners Ericsson and Qualcomm, Telstra has now delivered world first capability to ensure LTE-B can be delivered as efficiently as possible. Service Continuity will allow devices to transition in and out of LTE-B coverage areas without interruption. For instance, you might be at a music festival streaming an event on your phone but need to leave the venue and make your way back home (where LTE-B is not in use). Service Continuity means you can continue to watch the stream and the transition will be seamless – even though you have the left the broadcast area. Taking that a step further, MooD allows the network to determine how many LTE-B compatible devices in any given area are consuming the same content. MooD then intelligently activates or deactivates LTE-B, ensuring the mobile network is as efficient as possible in that location. For example, if a die-hard football fan is streaming a match we will likely service that one user with unicast, as that is the most efficient way of delivering the content. However if more users in the same cell decide to watch the match, MooD makes the decision automatically as to whether it is more efficient to service those users by switching the stream to broadcasting instead of individual unicast streams.
Its good to see Ericsson & Qualcomm finally taking eMBMS to commercial deployment. Back in 2015, I added their videos from MWC that year. See post here.
I think the Telstra post already provides info on why MooD is needed but this picture from Qualcomm whitepaper above makes it much clearer. Back in 3G MBMS and early days or eMBMS, there used to be a feature called counting, MooD is effectively doing the same thing.
For Service Continuity, this paper 'Service Continuity for eMBMS in LTE/LTE-Advanced Network: Standard Analysis and Supplement' by Ngoc-Duy Nguyen and Christian Bonnet has interesting proposal on how it should be done. I cannot be sure if this is correct as per the latest specifications but its interesting to learn how this would be done when the user moves out of coverage area in Idle or connected mode.
Note that this Expway paper also refers to Service continuity as Session continuity.
This year at MWC, I took the time out to go and see as many companies as I can. My main focus was looking at connectivity solutions, infrastructure, devices, gadgets and anything else cool. I have to say that I wasn't too impressed. I found some of the things later on Twitter or YouTube but as it happens, one cannot see everything.
I have to be honest, haven't seen a WOW demo yet at #MWC18. While there are lots of interesting stuff, it's all the same, old and tired stuff.
I will be writing a blog on Small Cells, Infrastructure, etc. later on but here are some cool videos that I have found. As its a playlist, if I find any more, it will be added to the same playlist below.
The big vendors did not open up their stands for everyone (even I couldn't get in 😉) but the good news is that most of their demos is available online. Below are the name of the companies that had official MWC 2018 websites. Will add more when I find them.
Its been a year since I last posted about Augmented / Virtual Reality Requirements for 5G. The topic of Virtual Reality has since made good progress for 5G. There are 2 technical reports that is looking at VR specifically. They are:
Anyway, back in Dec. 3GPP and Virtual Reality Industry Forum (VRIF) held a workshop on VR Ecosystem & Standards. All the materials, including agenda is available here. The final report is not there yet but I assume that there will be a press release when the report is published.
While there are some interesting presentations, here is what I found interesting:
From presentation by Gordon Castle, Head of Strategy Development, Ericsson
From presentation by Martin Renschler, Senior Director Technology, Qualcomm
For anyone wanting to learn more about 6 degrees of freedom (6- DoF), see this Wikipedia entry. According to the Nokia presentation, Facebook’s marketing people call this “6DOF;” the engineers at MPEG call it “3DOF+.”
XR is 'cross reality', which is any hardware that combines aspects of AR, MR and VR; such as Google Tango.
From presentation by Devon Copley, Former Head of Product, Nokia Ozo VR Platform
Some good stuff in the pres.
From presentation by Youngkwon Lim, Samsung Research America; the presentation provided a link to a recent YouTube video on this presentation. I really liked it so I am embedding that here:
Finally, from presentation by Gilles Teniou, SA4 Vice chairman - Video SWG chairman, 3GPP
You can check and download all the presentations here.
More than 23,500 patents have been declared essential to the GSM & 3G as shown in the picture above. I am assuming this includes 4G as well. Anyway, its been a while I looked into this subject. The last time I was looking, 4G patent pools were beginning to form.
For LTE, indeed there is no one-stop shop for licensing. The only company that has tried is VIA Licensing, with their patent pool, but they don’t have licenses for the big players like Ericsson, Qualcomm, Huawei, ZTE, Samsung, etc. The same will probably apply for 5G.
This old picture and article from Telecom TV (link) is an interesting read on this topic.
This official WIPO list shows ZTE, Huawei, and Qualcomm at the top of the list for international patent filers worldwide in 2016 [PDF].
Back in 2015, NGMN alliance was also looking for creation of some kind of patent pool but it probably didn't go anywhere (link)
(Can't recall the source for this one) In March, Ericsson announced plans to license 5G for $5 per device and possibly as low as $2.50 in emerging markets. In November, Qualcomm announced plans to license 5G IP at the same rates established by the NDRC for 4G/LTE phones sold into China: 2.275% for single mode essential patents / 4.0% for the entire portfolio or 3.25% for multimode essential patents / 5.0% for the entire portfolio. All rates are based on the wholesale price of the phone. Qualcomm also announced that the previously undisclosed $500 price cap will apply to all phones. Qualcomm also announce a rate of less than $5 for 5G for automotive applications and $0.50 for NB-IoT based IoT applications.
Ericsson has filed patent application for its end-to- end 5G technology. Ericsson has incorporated its numerous 5G and related inventions into a complete architecture for the 5G network standard. The patent application filed by the leading telecom vendor combines the work of 130 Ericsson inventors. Dr. Stefan Parkvall, Principal Researcher at Ericsson, said, “The patent application contains Ericsson’s complementary suite of 5G inventions.” Stefan added, “It contains everything you need to build a complete 5G network. From devices, the overall network architecture, the nodes in the network, methods and algorithms, but also shows how to connect all this together into one fully functioning network. The inventions in this application will have a huge impact on industry and society: they will provide low latency with high performance and capacity. This will enable new use cases like the Internet of Things, connected factories and self-driving cars.” Ericsson is involved with leading mobile operators across the world for 5G and Pre-5G research and trials. The patent application is likely to further strengthen its position in the 5G race.
More details on E/// 5G patents on their official website here.
Smartphone vendors will have to pay as much as $16.25 per device to use Qualcomm’s 5G New Radio (NR) technology under new royalty guidelines released by the company. Qualcomm said it will implement a royalty rate of 2.275 per cent of the selling price for single-mode 5G handsets and a higher rate of 3.25 per cent for multi-mode smartphones with 3G, 4G and 5G capabilities. So for a $200 multi-mode device, for instance, Qualcomm noted a vendor would have to pay $6.50 in royalties per device. Royalties are capped at a $500 device value, meaning the maximum amount a smartphone vendor would have to pay would be $16.25 per handset. The company added it will also offer access to its portfolio of both cellular standard essential patents and non-essential patents at a rate of 4 per cent of the selling price for single-mode devices and 5 per cent for multi-mode devices. Qualcomm’s rates are notably higher than those announced by Ericsson in March. The Swedish company said it would charge a flat royalty fee of $5 per 5G NR multimode handset, but noted its fee could go as low as $2.50 per device for handsets with low average selling prices.
The official Qualcomm 5G royalty terms [PDF] are available here.
Looking back at my old post about UMTS & LTE (re)selection/handovers, I wonder how many different kinds of handovers and (re)selection options may be needed now.
In another earlier post, I talked about the 5G specifications. This can also be seen in the picture above and may be easy to remember. The 25 series for UMTS mapped the same way to 36 series for LTE. Now the same mapping will be applied to 38 series for 5G. RRC specs would thus be 38.331.
A simple comparison of 5G and LTE RRC states can be seen in the picture above. As can be seen, a new state 'RRC Inactive' has been introduced. The main aim is to maintain the RRC connection while at the same time minimize signalling and power consumption.
Looking at the RRC specs you can see how 5G RRC states will work with 4G RRC states. There are still for further studies (FFS) items. Hopefully we will get more details soon.
3GPP TS 22.261, Service requirements for the 5G system; Stage 1 suggests the following with regards to inter-working with 2G & 3G
5.1.2.2Legacy service support The 5G system shall support all EPS capabilities (e.g., from TSs 22.011, 22.101, 22.278, 22.185, 22.071, 22.115, 22.153, 22.173) with the following exceptions: -CS voice service continuity and/or fallback to GERAN or UTRAN, -seamless handover between NG-RAN and GERAN, -seamless handover between NG-RAN and UTRAN, and -access to a 5G core network via GERAN or UTRAN.
