Navigating the Airwaves: The Future of Spectrum in Wi-Fi and Cellular Networks

Peter Rysavy is the president of Rysavy Research LLC, the consulting firm that he has led since 1993, focusing on computer networking, wireless technology, and mobile computing. Recently he did a presentation for Oregon Chapter of IEEE Communications Society (ComSoc). The abstract of the talk states:

Wireless communication is fundamental to our digital society, with radio spectrum the key enabling resource. Understanding the critical role of spectrum provides deep insight into how wireless technologies function and how they will evolve. This enlightening talk delves into the ingenious advancements in Wi-Fi and cellular networks to harness spectrum, including increasing efficiency, deploying new bands, aggregating channels, and dynamically sharing spectrum. Despite huge progress, formidable challenges remain in meeting soaring demands for capacity, achieving global harmonization, and ensuring coexistence with existing services. 

Key takeaways:

• There is increasing demand for wireless spectrum from technologies like WiFi and 5G cellular networks, but the amount of usable spectrum is finite.
• Different spectrum bands have tradeoffs between coverage, capacity, and ability to support new technologies. The mid-band spectrum between 2 and 6 GHz is well-suited for 5G.
• Technologies are evolving to use spectrum more efficiently through techniques like carrier aggregation, advanced modulation, massive MIMO, and puncturing in WiFi 7.
• The US lacks a clear long-term national spectrum strategy and roadmap, putting it at a disadvantage compared to countries like China, which plan spectrum allocations years in advance.
• Spectrum sharing is complex with no one-size-fits-all solution, though approaches like beamforming, dynamic spectrum access databases, and sensing show promise if challenges are addressed.
• Harmonizing spectrum use globally through conferences helps drive economies of scale in devices and supports roaming, though the US diverges in some bands like 6 GHz assigned solely to WiFi.

The video of the talk is embedded below:

The slides are available here.

Related Posts: 

• The 3G4G Blog: Prof. Ted Rappaport Keynote at EuCNC & 6G Summit 2023 on 'Looking Towards the 6G Era - What we may expect, and why'
• The 3G4G Blog: New 5G NTN Spectrum Bands in FR1 and FR2
• Free 6G Training: Recent Advances on Terahertz (THz) communications
• The 3G4G Blog: New Tutorial on 5G Spectrum
• Telecoms Infrastructure Blog: Ericsson's Massive MIMO Handbook(s)
• Telecoms Infrastructure Blog: Samsung and Ericsson Talks Massive MIMO
• Free 6G Training: Can Ultra Massive MIMO deliver Terabit/s Broadband Connectivity in 6G?
• The 3G4G Blog - 6G: Above 100 GHz and Terahertz (THz) Frequencies
• Connectivity Technology Blog: The Evolution of Wi-Fi 7 (IEEE 802.11be EHT) to Wi-Fi 8 (IEEE 802.11bn UHR) 

Prof. Ted Rappaport Keynote at EuCNC & 6G Summit 2023 on 'Looking Towards the 6G Era - What we may expect, and why'

Prof. Ted Rappaport has featured a few times in our blog posts (see here and here). Today we look at his recent keynote at the EuCNC & 6G Summit 2023 on the topic 'Looking Towards the 6G Era - What we may expect, and why'. The abstract of the talk says:

Recent work has shown that the fundamentals of the radio propagation channel will enable mobile communications all the way to 900 GHz, offering bandwidths of tens of GHz. An amazing fact that is all but disregarded is that the three fundamental technological breakthroughs of 5G, namely millimeter wave technology, small cell densification, and massive multiple-input multiple-output (massive-MIMO) antenna systems, are paving the way for the next several decades of the wireless industry. This talk demonstrates how the 5G era will futureproof wireless networks as we enter the 6G era and beyond — an era of wireless cognition and human-style computing. In fewer than 20 years, wireless networks will carry information at the computation speed of the human brain. Yet, how will engineers ensure that we build these networks with sustainability and power efficiency in mind? This talk offers some solutions and promising areas of exploration to ensure the future 6G era is lightning fast yet kind to planet earth.

Next G Alliance has a nice short report looking at 'Terminology for Frequency Ranges'. Handy and useful charts - https://t.co/kfJFxcdUDo via @atisupdates @NextGAlliance #Free5Gtraining #3G4G5G #ATIS #NGA #5G #B5G #6G #Frequency #Spectrum #Bands #mmWave #cmWave #THz pic.twitter.com/Nyoh1X0asX

— Free 5G Training (@5Gtraining) July 25, 2023

Recently I had a discussion about mmWave, sub-THz, THz, etc. This chart in the Tweet above is handy with deciphering the 5G/6G spectrum terminology.

Prof. Rappaport covered quite a few topics on spectrum above 100 GHz and made a strong case for mmWave and Terahertz. The mmWave adoption for 5G hasn't yet taken off so we will have to see how enthusiastic the industry is for even higher frequencies. The other keynotes from the conference (see references below) argued for cmWave as the mid-band for 6G. We will have to wait and see where all this discussion goes.

The talk is embedded below:

Related Posts: 

• Free 6G Training: Recent Advances on Terahertz (THz) communications
• The 3G4G Blog - 6G: Above 100 GHz and Terahertz (THz) Frequencies
• The 3G4G Blog: Spectrum for 5G NR beyond 52.6 GHz
• Free 6G Training: Ericsson's Keynote at EuCNC & 6G Summit 2023 on '6G – Connecting a cyber-physical world'
• Free 6G Training: Nokia's and Docomo's Joint Keynote at EuCNC & 6G Summit 2023 on '6G getting into next gear'
• Free 6G Training: Huawei's Keynote at EuCNC & 6G Summit 2023 on 'On the Convergence Route for 6G'
• Free 6G Training: EuCNC & 6G Summit 2023 Panel Session on 'Sustainability challenges and opportunities for 6G'
• Free 6G Training: Samsung's 6G Spectrum Whitepaper Discusses Candidate Bands
• Free 6G Training: Do we need more Bandwidth or Higher Bandwidth Efficiency?
• Free 6G Training: 7 Defining Features of Terahertz (THz) Wireless Communications Systems 

New 5G NTN Spectrum Bands in FR1 and FR2

Release-17 includes two new FR1 bands for NTN; n255 (a.k.a. NTN 1.6GHz) and n256 (a.k.a. NTN 2GHz). The picture is from a slide in Rohde & Schwarz presentation available here. Quoting from an article by Reiner Stuhlfauth, Technology Manager Wireless, Rohde & Schwarz:

Currently, several frequency ranges are being discussed within 3GPP for NTN. Some are in the FR1 legacy spectrum, and some beyond 10 GHz and FR2. The current FR1 bands discussed for NTN are:

• The S-band frequencies from 1980 to 2010 MHz in uplink (UL) direction and from 2170 to 2200 MHz in downlink (DL) direction (Band n256).
• The L-band frequencies from 1525 to 1559 MHz DL together with 1626.5 to 1660.5 MHz for the UL (Band n255).1

These frequency ranges have lower path attenuation, and they’re already used in legacy communications. Thus, components are available now, but the bands are very crowded, and the usable bandwidth is restricted. Current maximum bandwidth is 20 MHz with up to 40-MHz overall bandwidth envisaged in the future [TR 38.811].

As far as long-term NTN spectrum use is concerned, 3GPP is discussing NR-NTN above 10 GHz. The Ka-band is the highest-priority band with uplinks between 17.7 and 20.2 GHz and downlinks between 27.5 and 30 GHz, based on ITU information regarding satellite communications frequency use.2 Among current FR2 challenges, one is that some of the discussed bands fall into the spectrum gap between FR1 and FR2 and that NTN frequencies will use FDD duplex mode due to the long roundtrip time.

6G Unified networks: Multi-Layer Multi-Dimension Multi-Band (ML-MD-MB) Topology via @RohdeSchwarz highlights the future 6G Satellite and Terrestrial Network Convergence Vision#3G4G5G #5G #B5G #6G #NTN pic.twitter.com/DHVIP9kw8J

— Zahid Ghadialy (@zahidtg) May 20, 2023

Worth highlighting again that the bands above, including n510, n511 and n512 are all FDD bands due to the long round trip times.

The latest issue of 3GPP highlight magazine has an article on NTN as well. Quoting from the article:

The NTN standard completed as part of 3GPP Release 17 defines key enhancements to support satellite networks for two types of radio protocols/interfaces:

• 5G NR radio interface family also known as NR-NTN
• 4G NB-IoT & eMTC radio interfaces family known as IoT-NTN

These critical enhancements including adaptation for satellite latency and doppler effects have been carefully defined to support a wide range of satellite network deployment scenarios and orbits (i.e., LEO, MEO and GEO), terminal types (handheld, IoT, vehicle mounted), frequency bands, beam types (Earth fixed/Earth moving) and sizes. The NTN standard also addresses mobility procedures across both terrestrial and non-terrestrial network components. Release 17 further includes Radio Frequency and Radio Resource Management specifications for terminals and satellite access nodes operating in two FR1 frequency ranges allocated to Mobile Satellite Services (i.e., n255 and n256).

You can read it here.

Related Posts: 

• The 3G4G Blog: 3GPP 5G Non Terrestrial Networks (NTN) Standardization Update
• Connectivity Technology Blog: 5G NR-NTN Demos make a Debut at MWC 2023
• Connectivity Technology Blog: Direct-to-Mobile Communications Using LEO Satellites gets a Step Closer
• Connectivity Technology Blog: TIP has launched 'Non-Terrestrial Connectivity Solutions' Group
• The 3G4G Blog: An Introduction to Non-Terrestrial Networks (NTN)
• Free 6G Training: Non-Terrestrial Networks (NTN) & Satellites - Taking 6G to the Stars
• The 3G4G Blog: How Many People are Still Unconnected in 2023 and Why? 

APT 600 MHz Band Gets Approval from 3GPP

The current 600 MHz 5G band (n71) is getting an extension as 3GPP approves plan for APT 600 MHz band. Back in April, the 29th meeting of the APT Wireless Group (AWG-29) organized by the Asia Pacific Telecommunity (APT) concluded with the final approval of the new APT 600 MHz band plan that hoped to open an additional 40+40 MHz prime UHF spectrum. A similar approach back in 2013 resulted in the 45+45 MHz in the 700 MHz band, known in 3GPP as n28.

3GPP TSG RAN 96 (all docs here) approved a new work item to standardize the APT 600 MHz band plan which was initially proposed by the ITU-APT Foundation of India (IAFI).

RP-221778 (revision of RP-221062), provides a detailed justification for this new band. Quoting from the document:

The 470-694 MHz frequency range is allocated to the broadcasting service and mobile service on a co-primary basis in ITU Region 3. The frequency band 470-698 MHz, or parts thereof, was identified by WRC-15 in 7 countries in Region 3 through new footnote No. 5.296A for use by those administrations as listed wishing to implement terrestrial IMT systems. In addition, there is interest from other significant markets to do the same. Elsewhere, USA, Mexico and several other countries in ITU Region 2 also identified this band for IMT through footnotes 5.295 and 5.308A. It is noted that resolves 2 of revised Resolution 224 (Rev.WRC-19) to encourage administrations to take into account results of the existing relevant ITU Radio communication Sector studies, when implementing IMT applications/systems in the frequency bands 694-862 MHz in Region 1, in the frequency band 470-806 MHz in Region 2, in the frequency band 790-862 MHz in Region 3, in the frequency band 470-698 MHz, or portions thereof, for those administrations mentioned in No. 5.296A, and in the frequency band 698 790 MHz, or portions thereof, for those administrations mentioned in No. 5.313A.

Spectrum below 1 GHz is expectedly well suited for mobile broadband applications.  In particular, the unique propagation characteristics of the bands below 1 GHz allow for wider area coverage, which in turn requires fewer infrastructures and facilitates service delivery to rural or sparsely populated areas. In this regard, the 700MHz ecosystem is growing swiftly: there are over 34 commercial networks deployments.  The APT700 band plan coming out from Region 3 played a huge role in its success globally. Outside of APAC, countries in Region 2 have adopted or plan to adopt the APT700 band plan (3GPP band 28) for LTE system deployments. The lower duplexer of APT700 plan has also been adopted for Region 1 since the conclusion of WRC-15.

As the utilisation of the 700MHz spectrum increases over time, it is desirable to look at additional spectrum that could be considered as a companion besides 3GPP Band 28. Therefore, the use of parts of the 600MHz band for the mobile broadband service would provide a vital means of delivering high quality, wide area broadband services including in rural areas and deep inside buildings. The timely availability of frequency arrangements is essential for the development of IMT specifications and standards and the early consideration by Administrations in the footnotes referred to above of suitable frequency arrangements. 

The APT region is very diverse and consists of highly developed and developing countries and some with extremely large and rural population base. The sub 1 GHz bands is well suited for the later.

During the last year or so, 3GPP RAN 4 has completed a study item on the feasibility of various duplex filter options for use in this band. The results of this study are documented in TR 38.860. This study was sent to the AWG in an LS RP-212629 in Sep 2021 with a request to provide guidance on a preferred band plan and information on regulatory aspects for the normative work to begin. The AWG 28 meeting has considered the request of the 3GPP and has provided a response to this LS. In this response the LS has indicated a preference for option B1 (full band) and has also requested for the work to begin immediately with a view to completion by Dec 2022. Additionally, the answers to the regulatory questions sought by the 3GPP have now been provided via a reply LS RP 221045.

The band plan for the option B1 that has a single duplexer or full band- is shown in Table 1 below.

The Tx-Rx is "reverse-duplex"; in other words, the downlink frequency band is below the duplex gap while the uplink frequency band is above the duplex gap. This arrangement is opposite to conventional notation; however, for this band, it provides the benefit of aligning the uplink band adjacent to 3GPP band 28 thereby minimizing interference conditions at the 703 MHz boundary.

Accordingly, the companies listed here request 3GPP to start normative work on the following option. 

• Option B1 with a single duplexer 

For anyone interested in studying this further might want to refer to 3GPP TR 38.860: Study on Extended 600 MHz NR band.

Related Posts: 

• The 3G4G Blog: LTE Band 13 mystery
• The 3G4G Blog - Radio Design Webinar: Optimising Your 700 MHz Deployments
• The 3G4G Blog: Minimum Bandwidth Requirement for 5G Non-Standalone (NSA) Deployment
• Operator Watch Blog: USA has an interesting mix of different types of 5G
• 3G4G: 50 Questions on Spectrum 

Qualcomm Explains 5G Millimeter Wave (mmWave) Future & Integrated Access and Backhaul (IAB)

We have covered various topics in our blog posts on millimeter wave spectrum and even going beyond 52.6 GHz in FR2. A Qualcomm webinar from back in January expands on many of the topics that I looked superficially in various posts (links at the bottom).

The following is edited from the Qualcomm blog post:

5G NR in unlicensed spectrum (NR-U) was standardized in Release 16 and it is a key enabler for the 5G expansion to new use cases and verticals, providing expanded spectrum access to mobile operators, service providers, and industry players. At the same time, we are starting to push the mmWave boundary to even higher bands toward the sub-Terahertz (i.e., >100 GHz) range. Expected in Release 17, 5G NR will support spectrum bands up to 71 GHz, leveraging the 5G NR Release 15 scalable numerology and flexible framework. This opens up 5G to operate in the globally unlicensed 60 GHz band, which can fuel a broad range of new applications and deployments.

One daunting challenge that mobile operators will face when expanding 5G mmWave network coverage is the cost of deploying additional base stations for mmWave, which usually requires new fiber optics backhaul installations. Release 16-defined IAB allows a base station to not just provide wireless access for its user devices (e.g., smartphones) but also the ability to backhaul wirelessly via neighboring base stations using the same mmWave spectrum. IAB opens the door to more flexible densification strategies, allowing mobile operators to quickly add new base stations to their networks before having to install new fiber to increase backhaul capacity. 

Release 16 established foundational IAB capabilities, such as dynamic topology adaptation for load balancing and blockage mitigation, and Release 17+ will further enhance IAB by bringing new features like full-duplex operation, topology redundancy, and ML-based network management.

Beyond IAB, there is a rich roadmap of other new features that can further improve 5G mmWave system performance and efficiency. The webinar embedded below is presented by Ozge Koymen, Senior Director, Technology, Qualcomm Technologies, Inc. It covers the following topics:

• Qualcomm's vision for 5G mmWave and the new opportunities it poises to bring for the broader ecosystem
• mmWave capabilities and enhancements coming in Release -16 and beyond
• Qualcomm’s role in mobilizing and democratizing 5G mmWave to usher in new experiences
• Latest update on the global commercial rollout of 5G mmWave networks and devices

Slides of the presentation are available here.

Related Posts:

• Free 6G Training: Spectrum for 5G, Beyond 5G and 6G research
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• The 3G4G Blog: Spectrum for 5G NR beyond 52.6 GHz
• The 3G4G Blog: 5G Integrated Access and Backhaul (IAB) Enhancements in Rel-17
• The 3G4G Blog: Carrier Aggregation (CA) and Dual Connectivity (DC)
• The 3G4G Blog: The Politics of Standalone vs Non-Standalone 5G & 4G Speeds 

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

Operator Watch Blog: Austria Gets New 5G Spectrum - https://t.co/jN3sdIeci8 featuring tweets from @JimStLeger @tefficient #3G4G5G #OperatorWatch #Spectrum #4G #5G #Austria #Europe #RTR #H3A #Drei #TMobile #TMA #A1 pic.twitter.com/FAPAZsIGnl

— 3G4G (@3g4gUK) October 3, 2020

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.

Radio Design Webinar: Optimising Your 700 MHz Deployments from 3G4G

Related Posts:

• Operator Watch Blog: Hungary Allocates 5G Spectrum in 700 MHz, 2.1 GHz and 3.6 GHz
• Operator Watch Blog: Austria Gets New 5G Spectrum
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• Operator Watch Blog: Italy's 5G Spectrum Auction Controversy
• Operator Watch Blog: Bhutan improving 2G, 3G & 4G coverage while preparing for arrival of 5G in 2022
• Operator Watch Blog: Malaysia Decides on Innovative Approach for 5G Spectrum
• The 3G4G Blog: Automated 4G / 5G HetNet Design
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An Introduction to Vehicle to Everything (V2X) and Cellular V2X (C-V2X)

We made an introductory tutorial explaining vehicle to everything. There are 2 different favours of V2X as shown in this tweet below

We have a new section on 3G4G homepage - Vehicle to Everything (V2X) - https://t.co/enOdeIcLE5#3G4G5G #V2V #V2X #V2I #V2P #V2N #CAVs #ConnectedCars #AutonomousCars #3GPP #Specifications #Standards #Whitepapers #Webinars

— 3G4G (@3g4gUK) June 28, 2020

One is based on IEEE 802.11p (802.11bd in future). It is known by different names, DSRC, ITS-G5, etc. The other is the cellular V2X or C-V2X. It started as basic D2D but has evolved over the time. The slides and video are embedded below but this topic will need revisiting with more details.

Intermediate: Vehicle to Everything (V2X) Introduction from 3G4G

Related Posts:

• Connectivity Technology Blog: Introduction to Connected and Autonomous Vehicles (CAVs)
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Carrier Aggregation (CA) and Dual Connectivity (DC)

This topic keeps coming up every few months with either someone asking me for clarifications or someone asking us to make a video. While I don't think I will mange to get round to making a video sometime soon, there are some excellent resources available that should help a new starter. Here they are in an order I think works best



The first resource that I think also works best is this webinar / training from Award Solutions. It covers this topic well and the image at the top of the post is a god summary for someone who already understands the technology.

It may also help to understand that in the 5G NSA can have 4G carrier aggregation as well as 5G carrier aggregation in addition to dual connectivity.

If you saw the video earlier, you noticed that DC actually came as part of LTE in Release-12. We covered it in our Telecom Infrastructure blog here. NTT Docomo Technical journal had a detailed article on 'Carrier Aggregation Enhancement and Dual Connectivity Promising Higher Throughput and Capacity' that covered DC in a lot more technical detail, albeit from LTE point of view only. The article is available here. A WWRF whitepaper from the same era can also provide more details on LTE Small Cell Enhancement by Dual Connectivity. An archived copy of the paper is available here.

Another fantastic resource is this presentation by Rapeepat Ratasuk and Amitava Ghosh from Mobile Radio Research Lab, Nokia Bell Labs. The presentation is available here and details the MCG (Master Cell Group) Split Bearer and SCG (Secondary Cell Group) Split Bearer, etc. This article from Ericsson also provides more detail on this topic while ShareTechNote takes it one level even deeper with technical details and signalling here and here.

So hopefully this is a good detailed starting point on this topic, until we manage to make a simple video someday.

5G Dynamic Spectrum Sharing (DSS)

5G Dynamic Spectrum Sharing is a hot topic. I have already been asked about multiple people for links on good resources / whitepapers. So here is what we liked, feel free to add anything else you found useful as part of comments.

Nice new whitepaper - Nokia dynamic spectrum sharing for rapid 5G coverage rollout - https://t.co/HdnTz4ZIgr

via @nokianetworks #Free5Gtraining #5G #5GNR #5GNetworks #Nokia #4G #5GSpectrum #Spectrum #DSS #DynamicSpectrum pic.twitter.com/APSnW9vrUp

— 5G Training (@5Gtraining) May 7, 2020

Nokia has a nice high level overview of this topic which is available here. I really liked the decision tree as shown in the tweet above. I am going to quote a section here that is a great summary to decide if you want to dive deeper.

DSS in the physical layer

DSS allows CSPs to share resources dynamically between 4G and 5G in time and/or frequency domains, as shown on the left of Figure 3. It’s a simple idea in principle, but we also need to consider the detailed structure at the level of the resource block in order to understand the resource allocations for the control channels and reference signals. A single resource block is shown on the right side of Figure 3.

The 5G physical layer is designed to be so similar to 4G in 3GPP that DSS becomes feasible with the same subcarrier spacing and similar time domain structure. DSS is designed to be backwards compatible with all existing LTE devices. CSPs therefore need to maintain LTE cell reference signal (CRS) transmission. 5G transmission is designed around LTE CRS in an approach called CRS rate matching.

5G uses demodulation reference signals (DMRS), which are only transmitted together with 5G data and so minimize any impact on LTE capacity. If all LTE devices support Transmission Mode 9 (TM9), then the shared carrier has lower overheads because less CRS transmission is required. The control channel transmission and the data transmission can be selected dynamically between LTE and 5G, depending on the instantaneous capacity requirements.

A nice webinar looking at 5G Dynamic Spectrum Sharing a.k.a. DSS. A simple explanation is, use MBSFN subframes to tell LTE users that these resource blocks are not available and then use that spectrum for 5G NR.https://t.co/ettybXHMWV pic.twitter.com/zq7BQ9ImdB

— 3G4G (@3g4gUK) December 7, 2019

The second resource is this Rohde & Schwarz webinar here. As can be seen in the tweet above, it provides nice detailed explanation.

Finally, we have a Comprehensive Deployment Guide to Dynamic Spectrum Sharing for 5G NR and 4G LTE Coexistence, which is a nice and detailed whitepaper from Mediatek. Quoting a small section from the WP for anyone not wanting to go too much in deep:

The DSS concept is based on the flexible design of NR physical layer. It uses the idea that NR signals are transmitted over unused LTE resources. With LTE, all the channels are statically assigned in the time-frequency domain, whereas the NR physical layer is extremely flexible for reference signals, data and control channels, thus allowing dynamic configurations that will minimize a chance of collision between the two technologies. 

One of the main concepts of DSS is that only 5G users are made aware of it, while the functionalities of the existing LTE devices remain unaffected (i.e. LTE protocols in connected or idle mode). Therefore, fitting the flexible physical layer design of NR around that of LTE is needed in order to deploy DSS on a shared spectrum. This paper discusses the various options of DSS implementation, including deployment challenges, possible impacts to data rates, and areas of possible improvements.

NR offers a scalable and flexible physical layer design depicted by various numerologies. There are different subcarrier spacing (SCS) for data channels and synchronization channels based on the band assigned. This flexibility brings even more complexity because it overlays the NR signals over LTE, which requires very tight coordination between gNB and eNB in order to provide reliable synchronization in radio scheduling.

The main foundation of DSS is to schedule NR users in the LTE subframes while ensuring no respective impact on LTE users in terms of essential channels, such as reference signals used for synchronization and downlink measurements. LTE Cell Reference Signals (CRS) is typically the main concept where DSS options are designated, as CRS have a fixed time-frequency resource assignment. The CRS resources layout can vary depending on the number of antenna ports. More CRS antenna ports leads to increased usage of Resource Elements (REs). CRS generates from 4.76% (1 antenna port) up to 14.29% (4 antenna ports) overhead in LTE resources. As CRS is the channel used for downlink measurements, avoiding possible collision with CRS is one of the foundations of the DSS options shown in figure 1. The other aspect of DSS design is to fit the 5G NR reference signals within the subframes in a way to avoid affecting NR downlink measurements and synchronization. For that, DSS considers the options shown in figure 1 to ensure NR reference signals such as Synchronization Signal Block (SSB) or Demodulation Reference Signal (DMRS) are placed in time-frequencies away from any collision with LTE signals.

MBSFN, option 1 in figure 1, stands for Multi-Broadcast Single-Frequency Network and is used in LTE for point-to-multipoint transmission such as eMBMS (Evolved Multimedia Broadcast Multicast Services). The general idea of MBSFN is that specific subframes within an LTE frame reserve the last 12 OFDM symbols of such subframe to be free from other LTE channel transmission. These symbols were originally intended to be used for broadcast services and are “muted” for data transmission in other LTE UE. Now this idea has been adjusted for use in a DSS concept, so that these reserved symbols are used for NR signals instead of eMBMS. While in general LTE PDCCH can occupy from 1 to 3 symbols (based on cell load), the first two OFDM symbols of such MBSFN subframe are used for LTE PDCCH, and DSS NR UE can use the third symbol. Using MBSFN is completely transparent to legacy LTE-only devices from 3GPP Release 9 onwards, as such LTE UE knows that these subframes are used for other purposes. In this sense this is the simplest way of deploying DSS. This method has disadvantages though. The main one is that if MBSFN subframes are used very frequently and it takes away resources from LTE users, heavily reducing LTE-only user throughput. Note that option 1 shown in figure 1 does not require LTE MBSFN Reference Signals to be used, because the MBSFN subframe is used to mute the subframe for DSS operation only, and LTE CRS shall only be transmitted in the non-MBSFN region (within the first two symbols) of the MBSFN subframe.

The two other options illustrated in figure 1 are dealing with non-MBSFN subframes that contain LTE reference signals. Option 2 is ‘mini-slot’ based; mini-slot scheduling is available in NR for URLLC applications that require extremely low latency. The symbols can be placed anywhere inside the NR slot. In respect to DSS, mini-slot operation just eliminates the usage of the symbols that contain LTE CRS and schedule only free ones for NR transmission. The basic limitation of this method comes from the concept itself. It is not very suitable for eMBB applications as too many resources are outside of NR scheduling. However it still can be utilized in some special cases like 30 kHz SSB insertion which will be described later in this paper.

Option 3 is based on CRS rate matching in non-MBSFN subframes, and it is expected to be the one most commonly used for NR data channels. In this option, the UE performs puncturing of REs used by LTE CRS so that the NR scheduler knows which REs are not available for NR data scheduling on PDSCH (Physical Downlink Shared Channel). The implementation of this option can be either Resource Block (RB)-level when the whole RB containing LTE CRS is taken out of NR scheduling, or RE-level where NR PDSCH scheduling avoids particular REs only. The end result of this method is that the scheduler will reduce the NR PDSCH transport block size as the number of REs available for scheduling become less in a slot.

VodafoneZiggo launching 5G in Netherlands using DSS from Ericsson in 1800MHz band. Due to spectrum situation in Ned this is all VZ has at launch so it's 5G on the icon but offering customers only 10% faster speeds than they can get with 4G. https://t.co/BLirTX8XjU

— Keith Dyer (@keithdyer) April 28, 2020

Personally, I am not a big fan of DSS mainly because I think it is only useful in a very few scenarios. Also, it helps operators show a 5G logo but doesn't provide a 5G experience by itself. Nevertheless, it can come in handy for the coverage layer of 5G.

In one of the LinkedIn discussions (that I try and avoid mostly) somebody shared this above picture of Keysight Nemo DSS lab test results. As you can see there is quite a bit of overhead with DSS.

Spectrum for 5G NR beyond 52.6 GHz

3GPP TR 38.807: Study on requirements for NR beyond 52.6 GHz has recently been revised with all the new information post WRC-19. There is a section that details potential use cases for this new spectrum.

New spectrum above 52.6 GHz – Potential use cases and deployment scenarios from a presentation by Kari Pajukoski, Oskari Tervo and Jari Hulkkonen, Nokia at the #6GSummit https://t.co/BqYPK7xpcz #Free5GTraining pic.twitter.com/6gqz0jCL3A

— 5G Training (@5Gtraining) January 16, 2020

Quoting from the specs:

The relatively underutilized millimeter-wave (mmWave) spectrum offers excellent opportunities to provide high speed data rate, low latency, and high capacity due to the enormous amount of available contiguous bandwidth. However, operation on bands in frequencies above 52.6GHz will be limited by the performance of devices, for example, poor power amplifier (PA) efficiency and larger phase noise impairment, the increased front-end insertion loss together with the low noise amplifier (LNA) and analog-to-digital converter (ADC) noise. In addition, bands in frequencies above 52.6GHz have high propagation and penetration losses challenge. Even so, various use cases are envisioned for NR operating in frequencies between 52.6GHz and 114.25GHz. Some of the use cases are illustrated in Figure 5.1-1 and following section provide detailed description of the uses cases. It should be noted that there is not a 1-to-1 mapping of use cases and wireless interfaces, e.g. Uu, slidelink, etc. Various wireless interfaces could be applicable to various uses cases described.

• High data rate eMBB
• Mobile data offloading
• Short-range high-data rate D2D communications
• Vertical industry factory application
• Broadband distribution network
• Integrated access backhaul (IAB)
• Factory automation/Industrial IoT (IIoT)
• Augmented reality/virtual reality headsets and other high-end wearables
• Intelligent Transport Systems (ITS) and V2X
• Data Center Inter-rack Connectivity
• Smart grid automation
• Radar/Positioning
• Private Networks
• Critical medical communication

There is quite detailed information for each use case in the document that I am not detailing here.

Getting ready for our 5G training next week - https://t.co/6YXW3YlDvD - this picture summarises the 5G mmWave frequency proposals pre #WRC15, approved for study at WRC-15 and available for IMT post #WRC19#3G4G5G #CWTechTrain #5G #Spectrum #5GTraining @cambwireless @UK_5G pic.twitter.com/KoWEpD89Pz

— 3G4G (@3g4gUK) March 3, 2020

It also details information on the allocation within the frequency range 52.6 GHz to 116 GHz in ITU Radio Regulation (see table below). The column with comments contains (a subset of) information on protection requirements for incumbent services. For the full details please refer to the Radio Regulations.

Quoting from the specs:

Within the range 52.6 to 116 GHz, the frequency bands 66-76 GHz (including 66-71 and 71-76 GHz) and 81-86 GHz are being studied under WRC-19 Agenda Item 1.13 for potential IMT identification. Results of sharing and compatibility studies, potential technical and regulatory conditions are included in Draft CPM Report, and the final decisions are to be made in WRC-19 with respect to IMT identification or no IMT identification, along with the corresponding technical and regulatory conditions.

For 66-71 GHz, Studies were carried out for the ISS, MSS (Earth-to-space) indicating that sharing is feasible, with a need for separation distance in the order of few kilometers for the case of MSS (space-to-Earth). The need for studies addressing interference from IMT towards RNS is still under debate. Thus, final conclusions in the regulatory and technical conditions for this band cannot be drawn.

For 71-76 GHz, studies were carried out for the FS, RLS and FSS (space-to-Earth) indicating that sharing with FS and FSS is feasible. However, additional limits of the IMT BS and UE unwanted emissions is needed to protect RLS in the adjacent frequency band 76-81 GHz.

For 81-86 GHz, studies were carried out for the FS, FSS (Earth-to-space), RAS (in band and adjacent band), EESS (passive) and RLS. Studies are not needed for the SRS (passive), as this service is dealing with sensors around other planets and no interference issue is expected. Studies were also not carried out for the MSS. The results of those studies indicate that sharing with FS, FSS and RAS (in band and adjacent band) is feasible. Notice that additional limits of the IMT BS and UE unwanted emissions would be needed to ensure protection of EESS (passive) in the adjacent frequency band 76-81 GHz and RLS in the adjacent frequency band 86-82 GHz.

An interesting paper looking at Waveforms, Numerology, and Phase Noise Challenge for Mobile Communications Beyond 52.6 GHz is available here.


Related Posts:

• The 3G4G Blog: Examples of 5G Use Cases & Applications
• The 3G4G Blog: 5G Private and Non-Public Network (NPN)
• The 3G4G Blog: 5G Integrated Access and Backhaul (IAB) Enhancements in Rel-17
• The 3G4G Blog: What is Industrial IoT (IIoT) and how is it different from IoT?
• The 3G4G Blog: 5G and Industry 4.0
• Connectivity Technology Blog: 5G Indoor Precise Positioning
• The 3G4G Blog: 5G eXtended Reality (5G-XR) in 5G System (5GS)

Prof. Andy Sutton: Backhauling the 5G Experience - Jan 2020

Prof. Andy Sutton has shared quite a few presentations and talks on this blog. His presentations from the annual 'The IET 5G Seminar' has made it to the top 10 for the last 3 years in a row. His talk from 2019, 2018 & 2017 is available for anyone interested.

The title of this year's conference was '5G 2020 - Unleashed'. The details are available here and the video of all the talks are here. As always, the slides and video is embedded below.

Slides

Prof. Andy Sutton: Backhauling the 5G Experience from 3G4G

Video


There are a lot of bands that keep on getting mentioned, especially in relation to backhaul. Here is a summary of these bands that would come handy.

Related Posts:

• Prof. Andy Sutton: 5G Radio Access Network Architecture Evolution - Jan 2019
• Prof. Andy Sutton: 5G Network Architecture, Design and Optimisation - Jan 2018
• Prof. Andy Sutton: 5G Network Architecture and Design Update - Jan 2017
• Prof. Andy Sutton #CWHeritage Talk: The History of Synchronization in Digital Cellular Networks
• Connectivity Technology Blog: An Introduction to Different Types of Backhaul
• 5G Evolution with Matthew Baker, Nokia
• Exploring Network Convergence of Mobile, Broadband and Wi-Fi
• 5G and Fixed-Mobile Convergence (FMC)

Private 4G / 5G Cellular Networks and Bring Your Own Spectrum

With 4G maturing, private cellular networks are finally getting the attention that they deserve and has been promised for quite a while. In a Industry Analyst event, Nokia announced that they are running 120+ private networks including transportation, Energy, Public sector, Smart cities, manufacturing and logistics, etc. (tweet below). The Enterprise Business division is now accounting for 5% of the revenue.

Interesting to see that Nokia is running 120+ private networks including:
* 24 in transportation
* 35 in Energy
* 32 in public sector and smart cities
* 11 in manufacturing and logistics#CWTechTrain
Nice tweet 👇 Details 👉 https://t.co/pU9gnuh5Wphttps://t.co/FHGM1e2JxK

— Zahid Ghadialy (@zahidtg) November 19, 2019

Ray Le Maistre, Editor-in-Chief at Light Reading, in an opinion on Telecoms.com pointed out:

One of the more immediate revenue stream opportunities right now is wireless private networks, and the good news is that this opportunity doesn’t require 5G. Instead, the potential looks set to be enhanced by the availability of a full set of 5G standards (including the yet-to-be concluded core network specs) and the maturity of associated technology.

In the meantime, 4G/LTE has already been the cellular foundation for an increasingly thriving wireless private networks sector that, according to ABI Research, will be worth $16.3 billion by 2025

Another market sizing prediction, this time by SNS Telecom & IT, pitches annual spending on private 4G and 5G networks at $4.7 billion by the end of 2020 and almost $8 billion by 2023. 

However this plays out, there’s clear anticipation of growing investment. What’s particularly interesting, though, is which organizations might pocket that investment. That’s because enterprises and/or organizations looking to benefit from having a private wireless network have a number of options once they decide to move ahead with a private network – here are three permutations that look most likely to me:

1. Build and run it themselves – technology vendors get some sales in this instance
2. Outsource the network planning, construction and possibly even the day-to-day. management of the network to a systems integrator (SI) – the SI and some vendors get the spoils. It’s possible here, of course, that the SI could be a technology vendor.
3. Outsource to a mobile network operator – the operator and some vendors will get some greenbacks.

For sure there will be other permutations, but it shows how many different parts of the ecosystem have some skin in the game, which is what makes this sector so interesting.

What’s also interesting, of course, is what the enterprises do with their private networks: Does it enhance operations? Help reduce costs? Create new business opportunities? All of the above?

Let’s not forget the role of the regulators in all of this. In the US the private wireless sector has been given a shot in the arm by the availability of CBRS (Citizens Broadband Radio Service) shared spectrum in the currently unlicensed 3.5 GHz band: This has given rise to numerous trials and deployments in locations such as sports stadiums, Times Square and even prisons.

In Germany, the regulator has set aside 100MHz of 5G spectrum for private, industrial networks has caused a storm and even led to accusations from the mobile operators that the move ramped up the cost of licenses in the spectrum auction held earlier this year.

In the UK, Ofcom is making spectrum available in four bands:

• the 1800 MHz and 2300 MHz shared spectrum bands, which are currently used for mobile services;
• the 3.8-4.2 GHz band, which supports 5G services, and
• the 26 GHz band, which has also been identified as one of the main bands for 5G in the future.

Slide shared by Mansoor Hanif, CTO, Ofcom at TIP Summit 2019

The process to enable companies and organizations (Ofcom has identified manufacturers, business parks, holiday/theme parks and farms as potential users) in the UK to apply for spectrum will go live before the end of this year, with Ofcom believing that thousands of private networks could be up and running in the coming years.

Dean Bubley from Disruptive Analysis recently spoke about BYOSpectrum – Why private cellular is a game-changer at TAD Summit. The talk is embedded below and is definitely worth listening:



TelecomPaper reported:

The German Federal Ministry for Economic Affairs and Energy said that companies can start to apply to use 5G frequencies in the 3.7-3.8 GHz range on industrial campuses. Local frequencies enable firms to build their own private networks, rather than rely on telecommunications providers to build networks. 

The Automotive Industry Association (VDA) and other industry associations including the VCI, VDMA and ZVEI have welcomed the allocation of frequencies for industrial campuses. According to VDA, several dozen companies have already registered their interest in such frequencies with the Federal Network Agency. 

The firms believe that 5G can replace existing networks, including WLAN, provide improved coverage of entire company premises, enable full control over company data and reduce disruption to public mobile networks.

The spectrum licences will be allocated based on the applicant's geographic footprint and use of a certain area. Prices also take account the area covered by the network, as well as the amount of bandwidth used and duration of the licence.

The formula for the prices is very interesting as shown in the tweet below

License fee formula for local frequency use published by the German regulator yesterday

Formula: fee = 1000 + B * t * 5 * (6a1 + a2)

* 1000: base fee in €
* B: bandwidth in MHz (10-100MHz)
* t: allocation time in years
* a: area in km²https://t.co/NuAPyMAYuQ#5G #IIoT@UK_5G pic.twitter.com/a4ullfkKze

— Sylvia Lu (@SylviaLuUk) November 1, 2019

Unsurprising to see @BoschGlobal apply for local 3.7GHz spectrum for #Private5G #5G networks at key site in Germany

Initially it's for "the lead plant for Industry 4.0 in Stuttgart-Feuerbach and the research campus in Renningen"https://t.co/1OJ3tksse3

— Dean Bubley (@disruptivedean) November 22, 2019

In Japan, NTT Docomo is working in co-operation with industry partners to help them to create their own private 5G networks. More announcements on this are expected at MWC next year.

Finally, I am running an Introduction to Private 4G /5G Networks Workshop with Dean Bubley on 04 Feb 2020. If this is an area of interest, consider attending it.

I will be running an "Introduction to Private 4G & 5G Networks" workshop / training along with Dean Bubley (@disruptivedean) on 04 Feb 2020 in London. Agenda and other details here: https://t.co/x6xsCpd946 @cambwireless @UK_5G #CWTechTrain pic.twitter.com/iwYzXyZzua

— Zahid Ghadialy (@zahidtg) November 18, 2019

Related Posts:

• Non-public networks (NPN) - Private Networks by another name

The Politics of Standalone vs Non-Standalone 5G & 4G Speeds

A short video (and slides) discussing the operator dilemma of standalone (SA) vs non-standalone (NSA) 5G deployment, frequency refarming and why 4G speeds will start reducing once SA 5G starts to be deployed.

Video




Slides

Opinion: The Politics of SA vs NSA 5G & 4G Speeds from 3G4G

Related Posts:

• 5G SpeedTests and Theoretical Max Speeds Calculations
• New Tutorial on 5G Spectrum
• Updated 5G Terminology Presentation (Feb 2019)
• 3GPP 5G Standardization Update post RAN#84 (July 2019)