5G & Satellite: Driving Forward the ‘Network of Networks’

Featuring panellists from varied GVF member organisations – Norsat International (a leading provider of innovative communication solutions that enable the transmission of data, audio and video for remote and challenging applications, with products and services including customisable satellite components, portable satellite systems, maritime solutions and satellite networks), SpaceBridge (a global market leader in broadband satellite communications systems technology, developing and providing satellite network equipment and services, including VSAT HUBs and Terminals for Point-to-Point, Point-to-Multi-Point, and Mesh typologies, as well as SCPC and broadcast modems for GEO and NGSO satellite constellations), and Liquid Telecom (a leading independent data, voice and Internet Service provider, specialising in supplying wholesale satellite and international carrier services to independent mobile and fixed telecommunications operators in developing countries) – and moderated by an expert in 5G and IoT from the European Space Agency, the topic of the integral relationship of 5G and satellite generated a thematically broad discussion, as well as prompting a large amount of attendee questioning from a worldwide audience of hundreds.

Opening with discussion on the fundamental point as to whether the satellite industry is clear on exactly where it stands as a partner respect in the phased transition to 5G as a networking architecture with multiple access technologies, comment focused around the extent to which the evolving 3GPP Standard is moving towards specifically citing key functional roles for “Non-Terrestrial Networks” and that this features in Release 17 of the standard. It was further pointed out that the positioning of satellite in the transition to 5G will be facilitated by the success of satellite in 4G.

In agreeing that it is the unique characteristics of satellite that make it so essential to realising the full potential of 5G, the panel addressed inter-related issues pertaining to the major opportunities for satellite in the 5G satellite communication market over the next decade, including with reference to the different rates of roll-out in different regions of the world, and the different use cases/applications where satellite is a good fit, bringing benefit for customers/end users whose concern is for service access everywhere with high-reliability, and which the service providers can offer cost-effectively.

Discussion revealed the technical/engineering initiatives which the satellite industry is developing and bringing to market to prevent or mitigate signal interference/disruption from 5G base stations located in proximity to C-band ground terminals; making those terminals 5G-ready. Spectrum sharing was also discussed, framed within the context of new engineering initiatives.

Given that 5G brings together multiple technologies – Evolved Packet Core; Network Function Virtualization & Software Defined Networks; and, Virtualization and Cloud Computing technologies – panellists explored the position of satellite within this complexity, and went on to discuss the nature of locating network intelligence and content at the data centre or at the edge, and at the potential for satellite to migrate from proprietary to open standards, building on innovation across the RAN community to accelerate 5G. In closing, the panel expressed a general view that “5G” and “satellite” evolve into a “network of networks” that no longer focuses on the technologies behind the solution.

Limited time left many audience questions, as submitted through the Zoom Q&A function, unanswered. These will be addressed in writing by the panellists with their responses featuring here shortly. For the extensive body of questions which were tackled during the webinar hour, you can still join-in by clicking here for the video recording.

Q & A continued….

The following questions were posed during the webinar but there was insufficient time to respond during the one-hour duration of the event. Thank you to our audience for taking an active part by asking questions, and to our panellists for their time to answer them after the webinar ended…

1. High speed VSAT can feed good chunk of bandwidth to remote areas to be covered with 5G by cellular phone operators. Will it cost more to consumers to pay for the services as simple as internet access? Thank you.

Michele Di Paolo: Typically such remote coverages are covered by Universal Service Obligations (USO) in which the gov’t collect fees from all the operators/subscribers and then use such funds to subsidize the Mobile Network Operators (MNO) to provide services in areas where the business case does not necessarily make sense. Also, govt mandate coverage demographics in exchange for spectrum rights and if MNO does not provide that coverage they typically have to pay fines into the USO to further the deployment of services. Usually, as part of this subsidy, the govt mandates that there cannot be a two tier pricing for mobile services and so plans should be relatively equivalent to plans available in urban areas. As I may have mentioned during the discussion, it has taken 4G 10yrs to get as far as it is now and it is still the tech of choice due to the spectrum which allows long range coverage. By 2025, only 15% of mobile connections will be 5G and you can bet that that will be 99.9% URBAN centric so look to 4G for remote area coverage at least for the next 4-5 years…

2. What is the minimum latency for 5G on satellite?

Michele Di Paolo: Delivery of 5G services themselves will not be affected in anyway by VSAT latency. All services can be delivered, however, it will be to a different level of performance metrics. It is not the technology or the transport medium which is the issue… it is the app which is being serviced. If the app is rendered useless due to delay, then that is unfortunate, but it is not the technology itself which is latency dependant.

For instance, ULLC is possible only when 5G NR is connected to 5GC, itself connected to local cloud resources allowing for virtually instantaneous (few msec) exchanges of data. Needless to say, ULLC should be considered a terrestrial and fiber connected service and you would not expect to run ULLC user cases over GEO or MEO, but LEO can potentially fit the bill.

On the MMC level, those same IOT device can also operate over GEO VSAT however, the data will be delayed by VSAT delay. We already see this today as Nb-IOT devices are already available and are being deployed over 4G over VSAT in markets around the world. Nokia has deployed 4G basestations servicing farmsteads with coverage spanning the farms and remote villages and the additional VSAT delay has no noticeable impact on IOT devices.

Finally, MBB (broadband) is also independent of latency…The MBB actually comes from the additional new spectrum available above 6Ghz (the so called FR2 spectrum range) which offers large spectrum blocks allowing Gbps of potential bandwidth. The caveat of that spectrum is that it is severely range limited (only a few 100 meters or so) so its use and practicality is limited for rural markets. Meanwhile. 4G in its current spectrum coupled with 8×8 MIMO antennas can provide upto 1Gbps of relatively longhaul coverage in the FR1 range.

3. Two issues with VSTA latency and high cost, having 5G technology how will these two will look like?

Michele Di Paolo: Unfortunately, 5G will not affect time and space..lol.

Cost of VSAT backhaul has continued to decline as capacity has increased with introduction of additional capacity. There is a trend which, should it continue, will see potential capacity prices below $200/Mbps in short period of time. This reduced pricing is what has enabled the successful and profitable deployments of 4G over satellite in many countries such as Brazil, Indonesia, and across all of LATAM and Asia in general. It is an ethical imperative to connect the unconnected and in doing so improve their lives and their contribution to the economies (this has been proven time and time again that cost of connectivity is far lower than contribution of that connectivity to GDP).

VSAT latency is a factor only in the case of GEO (MEO and LEO have no such issue) and even that latency is becoming less and less of an issue. For VSAT, people have looked to Performance enhancement Proxy (PEP) to improve throughput of IP over GEO and I am releasing a WhitePaper which I will be publishing on my LinkedIN account and I encourage people to look it up. I make the case that today, PEP is not necessarily anymore and that VSAT latency impact on data is not what it used to be. You cannot change impact of latency on voice and two way videoconferencing but the impact on web browsing and file transfers is not as bad as it used to be.

Traditionally, satellite has had to play catch up and try to fit itself into the xG solution. As I mentioned, 4G success (over satellite) comes as a result of convergence of 4 main technologies. 1. HTS satellite delivering huge increase in capacity to supplement the legacy GEO which was already running at near capacity and so was being sold at premium pricing; 2. New ground equipment which was able to take advantage of the HTS powerful beams to provide higher bits/hz and thereby deliver most bits/$ (reduce cost of Mbps delivered); 3. 4G IP backhaul and transport breaks away from legacy xG centric encapsulation (previous encapsulations and backhaul employed limited throughput and added about 25% overhead) and 4G eNb radio supporting intelligent local radio management (better overall 4G radio management and performance vs radio management across the satellite as was supported in 3G); 4. Intelligent redesign of web tcp resources in different operating systems (Windows, Linux, and Android) allowing for window scaling and allowing for tcp transfers over GEO reaching up to 3-4Mbps today…and website redesign employing http2 which allows for faster downloads from websites…

5G success with satellite will also be dependent on convergence of technologies. 5G is built upon the successful technologies launches of cloud, NFV and SDWAN (not the other way around BTW as those services pre-date 5G by many years). This time satellite operators are ready with SD-WAN solutions (allowing mobile operators the option of selective steering of high bandwidth/latency tolerant traffic over satellite), remote OTT cloud caching solutions (using satellite multicast and teaming with leading Internet companies like Google/Youtube, Facebook, Netflix, Amazon to offer subsidized local solution offerings), to 5G specific satellite offerings such as China’s GalaxySpace 5G satellite LEO which will align with 5G standards offering low cost terminals and 5G like broadband (where 5G NR resources are not available) offering for multiple verticals and in support of 5G NR backhaul as well. LEO will definitely be an enabler of backhaul for 4G/5G and satellite service providers such as Telesat are targeting this market, while LEO startups such as SpaceX are launching based on the premise that much of the market cannot expect 5G level bandwidth for many years to come… this is born by statistics such as only 15% of mobile subscribers will be 5G and 4G will only hit 59% subscribers by 2025. Penetration of 5G will grow rapidly after that due to the focus on urban where a majority of the population reside, however, it is still expected that 4G coverage will only hit 70% by 2030. As such, that broadband experience will still be out of reach for a large percentage of the population for about 10 yrs or so making LEO commercial offerings a potentially viable consumer offering.

4. Will C-Band by maintained for Maritime usage on Open Seas? and How do you think the Teleport side will be handled?

Dr Amie Chan: The teleport needs to located away from 5G interference as if it needs to be operate in the C-band for reception in the band allocated to 5G. If it is used for broadcast and does not need reception in the 5G spectrum, it should not be a problem.

5. At the end is it not about the link budget. C-band provides 99.95% availability but Ku-band is not that far at 99.85% availability. With Uplink Power Control and ACM Ku and Ka bands will be protected for fade. Comment?

Dr Amie Chan: Rain fade can be improve by providing a greater rain margin to improve your availability. Some ways to improve availability include: a bigger antenna, higher wattage BUC, Coding (ACM) where you are trading BW for power etc. Some studies have shown that rain fade may be partially minimize by keeping the feed and reflector as dry as possible., ie., under a radome or covering.
Michele Di Paolo: That is absolutely true and operators such as Intelsat and SES have spent a lot of time and money (incentives) to assist those large C-band customers (typically video content providers, cable drop offs, etc) to migrate to KU and have demonstrated that Ku high availability via ACM and Uplink Power Control. In the end, the cost to operator and customer to migrate is fixed cost which is many times lower than the value of the freed up spectrum.

6. Is there commercially available SIT equipment which can support 5G SAT connectivity? What will be the latency with deploying 5G SAT connection – can it reach latency which is realized currently on 5G mobile networks?

Michele Di Paolo: Today, I do not think such a SIT is available (I may be wrong) as I see these solutions as being more of an evolution of existing solutions. At SpaceBridge, we have our plans for this but it is still in the works. 5G satellite offerings as that proposed by China GalaxySpace are still not delivering end customer solution and so are still in eval phase.

7. Latency is overcome by TCP acceleration. Streaming broadband will be OK. Gaming, on the other hand, will be problematic.

Michele Di Paolo: Web browsing and downloads have improved via Intelligent redesign of web tcp resources in different operating systems (Windows, Linux, and Android) allowing for window scaling and allowing for tcp transfers over GEO reaching up to 3-4Mbps today…and website redesign employing http2 which allows for faster downloads from websites (see my whitepaper to be published this weekend). Upcoming http3 will run over UDP and maybe that will be the end of throughput limitations over VSAT… we will see. Nevertheless, for most, todays satellite experience is sufficient to give a decent user experience even without the need to employ PEP (my personal opinion).
Streaming over long delay links has also been improved so that the stall and caching we were so frustrated with many years ago seldom happens anymore on modern streaming services.
As question stipulates, any two-way quasi realtime will still be problematic especially in the gaming world. I am frustrated with my terrestrial DSL connection delay and so GEO satellite would be a killer for gaming, VR or other such services for which ULLC is designed to accommodate.

8. For Dr. Chan… when those stations move from C-band to Ku\Ka, can service be improved re: rain fade?

Dr Amie Chan: Rain fade can be improved by providing a greater rain margin to improve your availability. Some ways to improve availability include: a bigger antenna, higher wattage BUC, Coding (ACM) where you are trading BW for power etc. Some studies have shown that rain fade may be partially minimize by keeping the feed and reflector as dry as possible., ie., under a radome or covering.

Additional question posted via YouTube after watching the video recording…

9. Very interesting discussion, what is LNB saturation, can you explain more, how it happens, what are the factors, how we can overcome this problem?

Michael Schefter, NORSAT: An LNB is essentially an amplifier with a downconverter. The front end of the LNB is designed to amplify small signals and add very little noise. The downconverter is a mixer with affixed LO and the down converted signal is further amplified and presented to the receiver (modem). Amplifiers typically have a fixed gain and have a maximum output power. WE want the amplifier to operate in the linear portion of its operating range. Where gain is constant and a change in input provides a corresponding change in output. As the input power is increased, eventually we get close to the maximum output power of the amplifier the amplifier becomes non-linear. Gain is not constant and a change in input results in a small change in output. We refer to this as gain compression and as we approach the maximum output power of the amplifier changes in input no longer affect a change in output. This is saturation.

As we approach saturation we start to get increased intermodulation products which can cause interference and close to saturation even distortion of the output signals.

Saturation can occur in the front end of the LNB (before the mixer), at the mixer or in the amplifiers after the mixer. In a well designed LNB the output stages (IF amplifiers) start to saturate first.

In C-band the total output power of one polarization the satellite will usually result in total signal power at the output of the LNB of < 0 dBm. This is still within the linear range of the LNB. In cases with very large antennas or powerful satellites LNB output may be higher and may start to get close to saturation. A typical P1dB of an LNB is 5-9 dBm. LNBs with higher P1DB can handle more power.

5G signals are much more powerful than the received signals from the satellite and will saturate the LNB unless special filters are installed to attenuate the 5G signals. Even with filters the attenuated signal can cause problems on standard LNBs and it is better to use an LNB designed to handle higher power..

For further information please visit Norsat website, check out our relevant product sheet or watch the product webinars that provide information on the effects of 5G signals on LNBs and ways to mitigate this.