Thursday, 17 December 2020

Conditional Handover (Rel. 16) Explained

Although a couple of SON mobility robustness features have been introduced in LTE radio networks it is still a common problem in some network areas that a high number of handover failures leads to higher drop rates and large numbers of RRC Re-Establishments.

Often these problems occur due to quickly changing radio conditions in the handover preparation phase or after handover execution attempt. 

SON algorithms cannot cope with these dynamic changes of the environment, but improvement is possible if the UE itself is enabled to constantly monitor the radio quality during the handover procedure and finally select the best possible target cell from a list of candidate neighbors. This new feature defined in 3GPP Release 16 for both, NG RAN (5G SA NR) as well as E-UTRAN (LTE), is called "Conditional Handover". The figure below illustrates how it works.

(click on the picture to enlarge)

Step 1 is the RRC Measurement Report indicating that handover to a neighbor cell is required. However, this message contains a list of candidate neighbor cells.

In the figure it is assumed that each of these candidate cells is controlled by a different gNB. Hence, 3 XnAP Handover Preparation procedures are performed and each potential target gNB allocates radio resources for the UE and provides a handover command (NR RRC Reconfiguration message) that is sent back to the source gNB (step 2).

In step 3 the source gNB builds the conditional handover command, which is a NR RRC Reconfiguration message that contains a list of conditional reconfiguration options plus additional RRC measurement configurations that enable the UE to find out which of the possible target cells is the best fit. 

In step 4 the UE makes its handover decision and moves to the cell controlled by target gNB 1.

Here it sends in step 5 the NR RRC Reconfiguration Complete message. 

The target gNB 1 detects the handover completion based on the reception of the NR RRC Reconfiguration Complete message, performs NGAP Path Switch procedure (not shown in figure) and triggers the release of the UE context in source gNB on behalf of sending the XnAP UE Context Release message (step 6).

With this information the source gNB also detects the successful handover completion and orders in step 7 the release of the radio resources provided by target gNB 2 and 3 to which it sends the new XnAP Conditional Handover Cancel message.

As mentioned before the conditional handover is also possible for LTE radio connections. In this case X2AP is used instead of XnAP and LTE RRC instead of NR RRC.

The conditional handover can be performed for all kind of intra-eNB/gNB handover and X2/Xn handover. However, S1/N2 (NG-C) conditional handover is not allowed.


Monday, 14 December 2020

Huawei's Power Digitalization 2025 Summit


Back in October, Huawei held Better World Summit 2020 (a.k.a. "Win-Win Future" Global Online Summit). The theme of this online summit was "Power Digitalization 2025”. Experts and operators shared their ideas, vision and challenges. The following summary was shared by Huawei:

Today, how should global operators respond to opportunities and challenges brought by changes in the digital world, under the rapid development of digital technology and digital economy.

“Energy, as the foundation of the digital world, has become a key part and an important point of competitiveness in the digital economy.” Zhou Taoyuan, President of Digital Power Product Line, Huawei, pointed out that “The entire industry needs to attach greater importance to energy”

With the rapid development of emerging technologies such as 5G, cloud, AI, big data, and the IoT, a digital transformation has kicked off, opening the digital age where things are sensing, connected, and intelligent, "ubiquitous Connected, omnipresent intelligence" is becoming a reality. This has thrown the development of 5G and big data centers into the spotlight. But at the same time, the large-scale and rapid construction of 5G and data centers have brought huge challenges to energy infrastructure, such as increasing energy consumption, long construction periods, and high operation and maintenance costs.

“Pay-as-you-go model is becoming more popular in many countries, as data center owners are looking to a decrease their investment and turn their Capex into Opex. And that goes also for a number of other services as part of running and maintaining data center.” Lilia Severina,Global Major Accounts Director of Uptime Institute,talked about the insights into data center trends at the meeting. “Existing site energy facility cannot meet the power demands of 5G sites. There is a pressing need for reform and innovation in this area.Digitization,intelligent and integrated 5G power system enable faster, more affordable, and simpler 5G network deployment.” Liu Baochang, Deputy Director of Information Energy Department, China Mobile Group Design Institute Co., Ltd, expressed his opinion on the development trend and insights of site power in the 5G era.

Violaine Petit, Sales and Marketing VP of CRT Informatique, shared an interesting case about building data centers of CRT in a castle.“CRT did not just want to build something regular. We wanted to be different. We also wanted to invest in a meaningful project. Based on our business development and rejuvenating the castle, CRT successfully deployed two data centers in the castle to meet the dynamic digital development requirements of government and enterprise users. It can be said that the castle data center not only expands CRT's business boundary, but also can protects the country's cultural heritage, can be said to be two birds with one stone.”

Today, people lead a convenient life because of development of science and technology, while they also worry about the environment. How do we transit towards a net-zero carbon economy? Alberto Carrillo Pineda, Director of Science Based Targets, CDP, has his own view. “This includes changes in policies, technologies, economic structures and patterns of production and consumption, but the most important thing is that we change the way we live today. One of the changes is energy transition. Transitioning from fossil-based to clean and renewable energy and phasing out CO2 emissions in other parts of our economy.”

Zhou Taoyuan said, “Huawei integrates traditional power technologies and digital technologies to achieve power digitalization. In this way, we can use ‘Bit to manage Watt’, and provide simple, green, smart, and reliable digital power solutions to solve challenges faced by traditional power industry. ”

Fang Liangzhou, the Chief Marketing Officer of Huawei Digital Power Product Line, Huawei, said“Huawei uses a target network architecture to guide the planning, construction, O&M, and operation of digital power infrastructure, driving the rapid development of the digital economy. Concerning site power, Huawei proposes implementing 5G without increasing site power-related OPEX, and aims to reduce costs from three aspects as well as tapping into new sources. As for data centers, Huawei proposes a simple, green, smart, and reliable next-generation data center facility that uses the "four reconstructions" initiative to tackle issues such as long data center construction period, high energy consumption, and challenging O&M.”

In the future, Huawei will keep cooperating with global operators to face the challenges and seize the opportunities brought by the digital world. Huawei aims to inject green power into operators and help them grow business sustainably in the future. 

Surprisingly the only video I could find is on Periscope, embedded in the tweet above. You can jump on to the relevant sessions using the timestamps as follows

0:01:20 1. Opening Speech - Zhou Taoyuan, President of Digital Power Product Line, Huawei

0:07:14 2. Building a Net-zero Emissions Economy - Alberto Carrillo Pineda, Director of Science Based Targets, CDP

0:17:18 3. Trend and Insight of Site Power Facility in 5G era - Liu Baochang, Deputy Director of Information Energy Department, China Mobile Group Design Institute Co., Ltd

0:31:30 4. Perspective and Practice of Lithium Battery Application - José Pedro Nascimento, Network Director, Altice Portugal

0:40:10 5. Network Energy-Efficient Operation in EM Market - Li Yao, Deputy Director of NOC, China Mobile Pakistan

0:51:40 6. Trend and Insight of Data Center Facility - Lilia Severina, Global Major Accounts Director of Uptime Institute

1:10:30 7. Prefabricated Modular Data Center Case Sharing - Operator customers

1:16:20 8. Partnering To Power The Digital Datacenter - Violaine Petit, Sales and Marketing VP of CRT Informatique

1:25:10 9. New Era, New Power. PowerX 2025 Target Network - Dr. Fang Liangzhou, CMO of Digital Power Product Line, Huawei

Let me know what you think.

Monday, 7 December 2020

Nokia Lectures in Collaboration with Bangalore University

Nokia recently delivered some lectures virtually to Bangalore University students. The talks covered a variety of talks from LTE to 5G, Security & IMS. The playlist from Nokia is embedded below. The video contains following topics:

Part 1: 5G - General Introduction and IoT Specific Features
Part 2: 5G Overview
Part 3: Network Security Practices and Principles
Part 4: LTE Network Architecture - Interface and Protocols
Part 5: IMS - IP Multimedia Subsystem

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Monday, 30 November 2020

Three New Standards to Accelerate 5G Wireless Wireline Convergence (WWC)

It's been just over a year since I wrote a detailed post on what I called '5G and Fixed-Mobile Convergence (FMC)'. The technical term being used in the industry for this feature is Wireless Wireline Convergence (WWC). 

Broadband Forum, the communications industry’s leading open standards development organization focused on accelerating broadband innovation, standards, and ecosystem development has just announced the publication of three new standards to accelerate global 5G adoption. The press release said:

Building on the Forum’s mission to drive a future consolidated approach to 5G, the standards will reduce development time, as well as capex and opex, from the traditional disparate fixed broadband and 5G networks. Ultimately, they will deliver a common and managed broadband experience to the end-user whatever the final connectivity technology.

There are three major sets of technical specifications that have been finalized, including 5G Wireless Wireline Convergence Architecture (TR-470), Access Gateway Function (AGF) Functional Requirements (TR-456) and Device Data Model (TR-181). Together, these documents provide functions and interfaces for Fixed Mobile Convergence (FMC), the AGF, and customer premises equipment (CPE) such as 5G-enabled routers.

TR-470 – produced in conjunction with 3GPP – describes the 5G FMC architecture, providing a high-level guide for network architects and planners and enabling fixed and mobile functions to coexist over a shared infrastructure. This will facilitate multi-access connectivity and give consumers a seamless, access-independent service experience.


For operators, the network functions required to operate their infrastructure will be streamlined and common technology, on-boarding, training, services and subscriber management between fixed and mobile divisions can be achieved. Furthermore, additional revenue streams will be created, with FMC extending the geographical reach of 5G core networks and the service offering of fixed networks.

TR-456 describes the functional requirements of the AGF. The AGF resides between fixed access networks and the 5G core network to support 5G and wireline Residential Gateways, creating a truly converged deployment. Alongside this, Broadband Forum’s Device: 2 data model (TR-181 Issue 2 Amendment 14), which is used by User Services Platform (USP), has been extended to address 5G Residential Gateways. The Device: 2 data model applies to all types of TR-069 or USP-enabled devices, including end devices, Residential Gateways, and other network infrastructure devices

In addition, the Functional Requirements for Broadband Residential Gateway Devices (TR-124) specification is expected to be finalized in Q4 2020. Moving from the network into the home, TR-124 has been extended to add requirements related to the 5G Residential Gateway extending the 5G control plane to the premises to open up new service opportunities with real time fulfillment.

In the video below, David Allan, Work Area Director for Wireless-Wireline Convergence at Broadband Forum and Christele Bouchat, Innovation Group Director at Broadband Forum discuss what is coming up in the next phase of 5G work and what opportunities this has opened up for the industry

WWC has a great potential to allow wireline and trusted/untrusted Wi-Fi to work with 5G so I am hopeful that operators will adopt this sooner, rather than later.

Follow the links below to learn more about this feature.

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Monday, 23 November 2020

Radio Design Webinar: Optimising Your 700 MHz Deployments

 


Radio Design, the award-winning market leader in the provision of wireless infrastructure sharing solutions and RF filter systems, hosted a webinar last week focused on the deployment of the 700 MHz frequency band. This new 700 MHz spectrum is in great demand across the world, mainly due to its long anticipated use as low band 5G spectrum. The webinar explores the potential of this band, as well as how to prepare for potential challenges when deploying.

For people who are familiar with our trainings, we divide the spectrum into three layers, the coverage layer, the capacity layer and the high-throughput layer. 700 MHz is the most popular coverage layer spectrum worldwide.

The slide above from the webinar talks of the recent Austrian 5G Spectrum auction that we blogged about. See tweet below for details

In the webinar, slides and video embedded below, Radio Design’s founder – Eric Hawthorn – kicks things off by analysing the benefits of deploying the 700 MHz band in the real world, before passing over to Global Engineering Director – Steve Shaw – who explores some of the technical problems which can arise, as well as some of the solutions. Last but not least, COO and co-owner of Keima – Iris Barcia – provides her insight into the benefits of deploying the 700 MHz band.

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Friday, 20 November 2020

Business Role Models for Network Slicing and iRAT Mobility for Cellular Internet of Things (CIoT) in Release 16

 3GPP Release 16 describes business role models for network slicing and in TR 21.916 I found the figures below that I have pimped a little bit to illustrate an asset tracking use case for goods transported with a truck from Factory A to Factory B. 

Factory B is equipped with a 5G Non-Public Network (NPN) that broadcasts an NPN-ID or - if the network infrastructure is deployed by an operator - a Cell Access Group ID (CAG ID).

I would like to assume that in case of the scenario shown in 3GPP Figure 2-2 the asset tracking CIoT devices are able to access any necessary PLMN, Network Slice and NPN. This can be achieved e.g. by using an eSIM. 

So while the truck is at the location of Factory A the asset tracking "things" will connect to the private slice of Factory A provided by the operator of PLMN 1. Factory A is a tenant of this operator. This means: Factory A rented a virtual part of PLMN1 for private use and technically this rented virtual network part is realized by a NW slice. 

When the truck leaves Factory A and drives on the road (maybe a long distance) to Factory B the asset tracking data must be transmitted over public mobile network infrastructure. Depending on rural coverage this service can be offered by PLMN 2 (as in case of 3GPP figure 2-2) or by PLMN 1 (as in case of 3GPP figure 2-3).

In case of 3GPP figure 2-4 the operator of PLMN 1 is even able to provide the private slice along the road, which allows Factory A to stretch the coverage of their virtual private network (slice) over a very long distance.

Looking further into the Cellular IoT enhancements defined by 3GPP in Release 16 it turns out that actually there is no need for a nation-wide 5G coverage to realize at least the role models shown in the 3GPP figures 2-2 and 2-3.

Because Release 16 also defines co-existence and inter-RAT mobility between 5G CIoT traffic and 4G NB-IoT the operators of PLMN 1 and PLMN 2 may offer NB-IoT coverage along the road while the factories are covered with 5G NR frequency cells - as shown in my second figure below.  

It illustrates the great improved flexibility that Release 16 standards are offering for customized business solutions and monitoring the service quality is not a trivial task under these circumstances.  


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Tuesday, 17 November 2020

5G Non IP Data Delivery and Lightweight M2M (LwM2M) over NIDD

Earlier this year, MediaTek had announced that its MT2625 NB-IoT chip has been validated for LwM2M over NIDD on SoftBank Corp.’s cellular network across Japan. This achievement marks the first global commercial readiness of LwM2M over NIDD; a secure, ultra-efficient IoT communications technique that is being adopted by operators worldwide. The benefits of LwM2M over NIDD include security improvements, cost-efficient scalability and reduced power consumption.

LwM2M over NIDD is a combination of the communication technology "NIDD (Non-IP Data Delivery)" that does not use an IP address in LTE communication NB-IoT for IoT and the device management protocol "LwM2M (Lightweight M2M)" advocated by the Open Mobile Alliance. It's been a while since I wrote about Open Mobile Alliance on this blog. OMA SpecWorks is the successor brand to the Open Mobile Alliance. You can read all about it here.


OMA SpecWorks’ LightweightM2M is a device management protocol designed for sensor networks and the demands of a machine-to-machine (M2M) environment. With LwM2M, OMA  SpecWorks has responded to demand in the market for a common standard for managing lightweight and low power devices on a variety of networks necessary to realize the potential of IoT. The LwM2M protocol, designed for remote management of M2M devices and related service enablement, features a modern architectural design based on REST, defines an extensible resource and data model and builds on an efficient secure data transfer standard called the Constrained Application Protocol (CoAP). LwM2M has been specified by a group of industry experts at the OMA SpecWorks Device Management Working Group and is based on protocol and security standards from the IETF.

You can get all the LwM2M resources here and the basic specs of 'Lightweight M2M 1.1: Managing Non-IP Devices in Cellular IoT Networks' here.
The 5G Americas whitepaper 'Wireless Technology Evolution Towards 5G: 3GPP Release 13 to Release 15 and Beyond' details how Current Architecture for 3GPP Systems for IOT Service Provision and Connectivity to External Application Servers. It also talks about Rel-13 Cellular IoT EPS Optimizations which provide improved support of small data transfer over control plane and user plane. Control Plane CIoT EPS Optimization transports user data (measurements, ID, status, etc.) via MME by encapsulating user data in NAS PDUs and reduces the total number of control plane messages when handling a short data transaction. Control Plane CIoT EPS optimization, designed for small infrequent data packets, can also be used for larger data bursts depending in UE Radio capability.

User data transported using the Control Plane CIoT EPS Optimization, has special characteristics, as different mobility anchor and termination nodes.

Therefore, the Preferred Network Behavior signaling must include information on:
  • Whether Control Plane CIoT EPS optimization is supported
  • Whether User Plane CIoT EPS optimization is supported
  • Whether Control Plane CIoT EPS optimization is preferred or whether User Plane CIoT EPS optimization is preferred
These optimizations have enabled:
  • Non-IP Data Delivery (NIDD) for both: mobile originated and mobile terminated communications, by using SCEF (Service Capability Exposure Function) or SGi tunneling. However, it has to be taken into account that Non-IP PDUs may be lost and its sequence is not guaranteed
  • For IP data, the UE and MME may perform header compression based on Robust Header Compression (ROHC) framework
  • NB-IoT UE can attach but not activate any PDN connection
  • High latency communication handled by the buffering of downlink data (in the Serving GW or the MME)
  • SMS transfer
  • EPS Attach, TA Update and EPS Detach procedures for NB-IoT only UEs, with SMS service request
  • Procedures for connection suspend and resume are added
  • Support for transfer of user plane data without the need for using the Service Request procedure to establish Access Stratum context in the serving eNodeB and UE
When selecting an MME for a UE that is using the NB-IoT RAT, and/or for a UE that signals support for CIoT EPS Optimizations in RRC signaling, the eNodeB’s MME selection algorithm shall select an MME taking into account its Release 13 NAS signaling protocol.

Mpirical has a nice short video explaining 5G Non IP Data Delivery. It is embedded below.

IoT has not taken off as expected and prophesised for years. While the OMASpecWorks is doing some fantastic work by defining simplified approach for IoT deployment, its current member list doesn't have enough operators to drive the uptake required for its spec adoption. They would argue that it doesn't matter how many members there are as the NIDD approach is completely optional and over-the-top. Let's wait and see how it progresses.

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Tuesday, 10 November 2020

Network Slicing Tutorials and Other Resources

I have received quite a few requests to do a 5G Network Slicing tutorial but have still not got around to doing it. Luckily there are so many public resources available that I can get away with not doing one on this topic. 


This Award Solutions webinar by Paul Shepherd (embedded below) provides good insights into network slicing, what it is, how it efficiently enables different services in 5G networks, and the architectural changes in 5G required to support it.

Then there is also this myth about 3 slices in the network. The GSMA slice template is a good starting point for an operator looking to do network slicing in their 5G networks. The latest version is 3.0, available here.


As this picture (courtesy of Phil Kendall) shows, it's not a straightforward task.  

Alistair URIE from Nokia Bell Labs points out some common misconceptions people have with Network Slicing:

  1. Multiple slices may share the same cell and the same RU in each slice
  2. Single UE may have up to 8 active slices but must have a single CU-CP instance to terminate the common RRC 
  3. Slicing supports more than 3 slices 

Back in March, China Mobile, Huawei, Tencent, China Electric Power Research Institute, and Digital Domain have jointly released the Categories and Service Levels of Network Slice White Paper to introduce the industry’s first classification of network slice levels. The new white paper dives into the definitions, solutions, typical scenarios, and evolution that make up the five levels of network slices. It serves as an excellent reference to provide guidance in promoting and commercializing network slicing, and lays a theoretical foundation for the industry-wide application of network slicing.

The whitepaper describes the different phases as:

Phase 1 (ready): As mentioned above, the 5G transport network and 5G core network support different software-based and hardware-based isolation solutions. On the 5G NR side, 5QIs (QoS scheduling mechanism) are mainly used to achieve software-based isolation in WAN scenarios. Alternatively, campus-specific 5G NR (including micro base stations and indoor distributed base stations) is used to implement hardware-based isolation in LAN scenarios. In terms of service experience assurance, 5QIs are used to implement differentiated SLA assurance between slices. In terms of slice OAM capabilities, E2E KPIs can be managed in a visualized manner. This means that from 2020 on, Huawei is ready to deliver commercial use of E2E slicing for common customers and VIP customers of the public network and common customer of general industries (such as UHD live broadcast and AR advertisement).

Phase 2 (to be ready in 2021): In terms of isolation, the 5G NR side supports the wireless RB resource reservation technology (including the static reservation and dynamic reservation modes) to implement E2E network resource isolation and slicing in WAN scenarios. In terms of service experience assurance, features such as 5G LAN and 5G TSN are enhanced to implement differentiated and deterministic SLA assurance between different slices. In terms of slice OAM, on the basis of tenant-level KPI visualization, the limited self-service of the industry for rented slices can be further supported. In this phase, operators can serve VIP customers in common industries (such as AR/VR cloud games and drone inspection), dedicated industry customers (such as electric power management information region, medical hospital campus, and industrial campus), and dedicated industry customers (such as electric power production control region and public security).

Phase 3 (to be ready after 2022): In this phase, 5G network slicing supports real dynamic closed-loop SLAs based on AI and negative feedback mechanism, implementing network self-optimization and better serving industries (such as 5G V2X) with high requirements on mobility, roaming, and service continuity. In addition, industry-oriented comprehensive service capabilities will be further enhanced and evolved.

A more technical presentation from Nokia is available here. The video below shows how innovations in IP routing and SDN work together to implement network slicing in the transport domain.

If you know some other good resources and tutorials worth sharing, add them in the comments below.

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Monday, 2 November 2020

Lawful Intercept in 5G Networks

Mats Näslund is a cryptologist at the National Defence Radio Establishment outside Stockholm, an agency under the Swedish dept. of defence. As part of his work, he represents Sweden in technical LI standardization in 3GPP. Mats also has a part time appointment as adjunct professor at KTH. Her recently delivered a HAIC Talk on Lawful Intercept in 5G Networks. HAIC Talks is a series of public outreach events on contemporary topics in information security, organized by the Helsinki-Aalto Institute for Cybersecurity (HAIC).


The following is the description from HAIC website:

Our societies have been prospering, much due to huge technological advances over the last 100 years. Unfortunately, criminal activity has in many cases also been able to draw benefits from these advances. Communication technology, such as the Internet and mobile phones, are today “tools-of-the-trade” that are used to plan, execute, and even hide crimes such as fraud, espionage, terrorism, child abuse, to mention just a few. Almost all countries have regulated how law enforcement, in order to prevent or investigate serious crime, can sometimes get access to meta data and communication content of service providers, data which normally is protected as personal/private information. The commonly used term for this is Lawful Interception (LI). For mobile networks LI is, from a technical standpoint, carried out according to ETSI and 3GPP standards. In this talk, the focus will lie on the technical LI architecture for 5G networks. We will also give some background, describing the general, high-level legal aspects of LI, as well as some current and future technical challenges.

The slides are available here.

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Monday, 26 October 2020

Understanding the TCO of a Mobile Network

TCO or 'Total Cost of Ownership' is an important topic for the mobile networks. The service providers use it to ascertain how much the network will cost and based on that they decide what they should charge and how much money could make. 

In this basic tutorial, we looks at the basic costs in the mobile network, eventually looking at the CapEx and OpEx of RAN and look at how some operators try to reduce the these costs. Slides and video embedded below.

Would love to hear your thoughts and anecdotes.

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