Introduction to G.hn EoC Technology
Bringing Gigabit all the way Home
Steve Staples FSCTE – Technical Sales Support Manager
As the demand for ever faster speeds and bandwidth increases, the FTTH roll-out in the UK continues at some considerable pace.
At the time of writing, more and more Homes and Apartment Blocks across the UK are being passed with Gigabit Fibre. However, this huge roll out exercise can sometimes fail at the final hurdle if home or building owners do not agree to the additional expense and disruption often incurred due to extensive re-cabling works (sometimes required within MDU residential properties or SDU homes) to get the Gigabit Network capability to where it is needed within the property. This is a common problem and there is a lot of misinformation out there.
Once fibre has arrived at or in a building, many network operators and home owners are faced with the question of how to bridge the last few metres to the Apartments in MDU, or the rest of the Home in a SDU. If the existing building is not easy to re-cable (or it is a listed building), then the use of the existing coaxial cable network presents an ideal, cost effective and environmentally friendly solution.
Ethernet over Coax or “EoC”, utilises G.hn Wave 2 Technology and is often able to provide a solution to this conundrum by providing that missing link from the fibre termination point to the rest of the home or building.
Most consumers, if they have full fibre broadband, assume the speed at their front door will be the speed available throughout their property. This can be difficult to achieve with alternative technologies such as Mesh, Wi-Fi or Powerline. In MDU’s, the use of existing legacy telephone cabling is also not ideal and prone to incurring service level issues resulting in frustrated clients.
EoC provides for a seamless transition from the fibre optic network, usually GPON, to the in-house coaxial cable network, delivering the full benefit of full fibre to places other technologies cannot reach. EoC utilises a more robust transmission path of screened coax cable, ensuring the same level of full fibre performance, as is delivered to the door, is received anywhere a coax outlet is installed.
EoC achieves this by employing G.hn wave 2 technology, which uses the lower frequency range of 2 to 200 MHz on the coaxial cable. Using this lower frequency range allows far greater distances to be achieved than traditional structured cable such as Cat6, whilst maintaining the Gigabit Network performance right to the end of the coax cable where it is required.
If they are required, use of this lower frequency band also allows for the continued use of DVB-C, DVB-T and DVB-S services down the same coax cable. DVB-S requires a multiswitch with a passive terrestrial path or alternatively, can be combined on to the coax cable after the multiswitch and separated before the end point with a TV/SAT Diplexer.
EoC enables a data rate of up to 1.6 Gbit/s on the coaxial cable between an EoC controller and any end points. It doesn’t matter whether the end points are connected via a star-shaped coaxial distribution or via a tree and branch structure, they will still connect to the EoC controller. The G.hn signal becomes available in all connected rooms/flats at any end point position to reproduce the incoming speed at the RJ45 Ethernet Port of the end point whilst maintaining any TV signal on its TV Out Port.
If VHF radio channels below 200 MHz are still required, these frequency ranges can be masked out by in-built electronic notch filtering in the EoC controller. These frequencies will then not be used for data transmission (but it should be noted that the achievable data rate will decrease as a result).
However, test measurements have shown, that even if only a frequency range of around 85 MHz of the normal 198 MHz is available, a symmetrical net data throughput of 550 Mbit/s is still possible. Latency too is minimal at ~ 1 ms.
To maximise the performance of any EoC system it is recommended to “clear” the frequency band between 2 to 200 MHz and wherever possible only use outlet plates that do not have built-in filtering (to ensure this frequency range passes to the end point unhindered), ensuring maximum bandwidth and throughput is achieved.
What is G.hn Wave 2 Technology?
G.hn is a protocol and ITU Standard, which when employed as EoC basically converts data packets from an ethernet connection into a signal of QAM modulated OFDM sub-carriers that is transmitted over a coax cable and converted back to data packets via an ethernet connection again. In effect it replicates a direct ethernet connection but with some added, distinct advantages
ITU G.hn is a next-generation, unified coaxial, phone line and power line home networking standard. Even if the main target for this standard is in-home networks, the same technology can also be used in access networks when the access features are implemented on top of the standard-based solution.
Compared to all other Coax technologies, G.hn wave 2 has more bandwidth, lower latency, fewer errors and uses a more manageable frequency. It also compares well to fibre solutions.
It can be used with most existing TV solutions without channel reallocation and the G.hn wave 2 technology offers a data rate of 1.6 gigabit per second (1.6 Gbps). The G.hn link between the EoC controller and the end points can be limited by other factors such as noise and attenuation but generally will maintain a link speed of up to 1.6 Gbps.
The ethernet interface will normally have a limit of 1 gigabit per second (1 Gbps). As a consequence, the max throughput of an EoC system is 1 Gbps duplex.
Normally an Internet connection will have a download (DL) and an upload (UL) speed. i.e: 50 / 10 Mbps. G.hn wave 2 bandwidth is 1,600 Mbps total (simplex), and this will be dynamically distributed between download and upload.
This means that G.hn throughput can be anywhere between:
800 / 800 Mbps
1,000 / 600 Mbps
600 / 1,000 Mbps
It is often possible to isolate or notch out specific frequencies i.e. the FM band from 88 – 108 MHz .
This would result in a 10% bandwidth loss (200 MHz – 20 MHz) resulting in a combined bandwidth for up/downstream of 1,440 Mbps.
Or it is possible to limit the frequency used to 0-100 MHz resulting in 50% bandwidth loss leaving 800 Mbps of bandwidth.
Commonly, tap and splitter frequencies start at 5 MHz – resulting in around a 2.5% loss of G.hn bandwidth but tests have shown that it is still possible to maintain link speeds in excess of 1,500 Mbps.
Comparative Technologies
EoC G.hn Wave 2 Technology additionally provides significant advantages over other, similar comparative technologies. The two main comparative technologies are MoCA and DOCSIS. MoCA and DOCSIS both use the frequency range above 470 MHz, so inevitably come into conflict with existing TV services and also require good quality coax cable in the network. By using the lower frequency range up to 200 MHz, EoC G.hn technology is very robust and copes well with older cable networks, where higher attenuation levels can occur and also means there is less potential for conflict with any existing services. If FM frequencies need “notching” out in the G.hn band this would as explained reduce bandwidth, however FM is much less of a concern, as it is likely to cease in the very near future and most, if not all, FM Radio Services are now available on DAB or available to Stream.
The MoCA 2.5 (Multimedia over Coax Alliance D-Band) system in particular uses the upper frequency range above 1,000 MHz so often the existing components in a CATV/MATV Network would need to be replaced, as they are usually only designed up to a frequency of 862 or sometimes 1,000 MHz.
Like MoCA, DOCSIS 3.0 also requires far greater bandwidth to deliver a performance level equivalent to EoC and will struggle to meet the same performance levels on older cable Networks. (Figure 1)
Although DOCSIS 3.1, now known as DOCSIS 4.0 (or 3.1 full duplex) is capable of speeds up to 10 GHz, this cannot co-exist with DTT or Satellite services in a converged system as G.hn can. G.hn technology is technically capable of 10 Gbps but not yet generally, commercially available, although as the need for speed increases going forward, G.hn EoC Products will no doubt evolve to meet that demand.
So there are many advantages to using G.hn in coax networks. One core advantage of course is the transmission path being re-purposed, in this case, the coax. Coax networks are usually well screened and therefore not so prone to interference from outside sources and can provide far better immunity to EMI. Although the technology behind G.hn is complex, the deployment could not be more simple (Figure 2).
Ethernet over Coax in SDU
FTTH is revolutionizing Broadband delivery to Home Owners and many households manage their needs quite comfortably from a single router positioned near, where traditionally, their main landline telephone socket is located. This may be in the hallway or lounge, or if a newer build property, perhaps under the stairs or utility cupboard in the kitchen. The location of the router has a huge impact on its performance.
However, all too often, a single router within the property is not sufficient to serve all the needs of the home owner. In many cases, residents struggle to stream or game comfortably around the house. This can be down to many factors, for example, a low powered ISP router, distance from the router to the wireless client itself, wall construction type, airborne interference and Wi-Fi congestion – these can all play a part in slowing down the speed of their connection. This is most noticeable with FTTH, where speeds of 500 Mbps or more are not uncommon and can be enjoyed (with the right device) next to, or hardwired to their router. However, in their bedroom or conservatory at the rear of their house, they can end up with very poor connectivity and low speeds by comparison, which lead them to suffer buffering or loss of connectivity.
There are several options available to potentially overcome this, and other means of getting the data to where it is needed are often employed. Some are more effective than others and some are more robust and reliable too. Hardwiring however, is always the preferred choice as this provides the most reliable and robust connectivity without loss of speed or bandwidth. With CAT6 for example, a Gigabit can be maintained up to around 90m which is adequate for most domestic environments, but what if you need to get connectivity to an outbuilding over 90m away or you cannot run a new Ethernet Cable for some reason? Perhaps the customer does not want the mess or disruption to their property that would be involved in running in that new ethernet cable, or there is no discrete way to route it. This is where EoC is the perfect solution. No drilling, no mess and an instant, reliable and robust Gigabit network to their home in minutes and capable of delivering a Gigabit up to 500m. (Figure 3)
The figures in the above table are based on attenuation levels when using good quality type 100 cable, and although 500m is not likely to be required in a domestic setting, the point to note is that the attenuation level at that distance is around 40 dB in the EoC G.hn frequency range of 2-200 MHz.
This demonstrates that even when using older existing cables in a property, which may be poor quality, with high attenuation levels, EoC will still perform as intended over what are generally shorter distances. It should also be noted that TV services are unlikely to travel the same 500m and above. EoC functionality at these distances is really intended for Data only applications and as you can see from the table, you can still achieve around 50 Mbps after 1 km of coax.
As the reception of TV in the Home moves ever closer towards a streaming future, EoC is an ideal means of providing robust and reliable Gigabit connectivity to any TV or room that is connected to a legacy terrestrial TV system.
Ethernet over Coax in MDU
In a typical block of apartments with an existing IRS system in place, the G.hn signal can be fed into a coaxial network via the passive terrestrial antenna input on a multi-switch (must be passive and capable of passing 2-200 MHz) and the EoC signal would then be available in all connected flats
(Figure 4)
Where an existing Coax Network has an amplifier or other component that will not pass 2-200 MHz then a bypass filter can be used to separate the TV and EoC signal to allow the EoC signal to bypass the Amplifier unhindered and re-combine the G.hn signal with the TV signal again into the coax network again on the other side of the filter. (Figure 5)
EoC has for many years been successfully used in hotels, hospitals, camp sites and nursing homes – in fact anywhere there was an existing coax network in place. A typical EoC system will usually consist of a controller (Figure 6), which is often available with two or four G.hn coax output ports, and various types of end points that provide the transition back from G.hn to Gigabit Ethernet or WLAN. The example shown (Figure 6) is capable of up to 16 end points per G.hn coax port or a string of up to 64 end points by physically combining the G.hn ports.
For ISP or network operators, there are media converters which can work as “network blind”, so they do not have to worry about how to manage or configure them and they can easily be installed by the end customer in their home (Figure 7). It is equipped with a Gigabit Ethernet interface for connecting to End-User CPE such as a modem or router or any network enabled device such as a smart TV, streaming device, games console, Wi-Fi Access point etc. There is also a coaxial F jack to enable connection to a local TV to ensure reception of any TV services is maintained.
When more G.hn EoC end points are used, sharing the same coax medium, the G.hn bandwidth will be distributed fairly between them. The bandwidth will be adjusted dynamically and on demand, ensuring that each end point gets its own fair share. When only a single end point needs to transmit or receive data over G.hn, it will utilize the entire bandwidth and as more end points need to transmit and receive, the bandwidth is then evenly distributed between all active end points. This compares well with traditional IP networks, where the bandwidth needs of individual clients are often asynchronous and spiky. In contrast to having a fixed fractional part of the bandwidth statically assigned for the individual MDUs this allows for a much better utilization of the bandwidth available.
It is however still possible to control how much bandwidth that can maximally be consumed by the individual end points. This may be desired by MDU operators, allowing them to limit or upsell more bandwidth to the individual MDU residents.
G.hn Wi-Fi end points can also be used, or standard Wi-Fi access points added to a media converter, to ensure robust in-room Wi-Fi to maximise speed and throughput in any environment.
This is particularly beneficial in MDU settings where congested wireless spectrum, due to large numbers of wireless routers all fighting for bandwidth, can lead to poor speeds and connectivity within Apartment Buildings (Figure 8).
Important to note is the additional advantage to Building Owners where good Internet connectivity and Wi-Fi can be achieved in every apartment without changes to the building’s structure which would otherwise involve consideration of matters such as fire protection etc, and without any significant service disruption or inconvenience to them or their residents.
Summary
“Convergence” is a term that was first used many years ago now, but as an Industry we are fast approaching the apex of the converging paths of traditional broadcasting and internet based TV.
As Installers adapt and learn new skills to ensure their futures within the Industry, G.hn EoC can play a major part in the upskilling and re-skilling of the Installer base. It is the perfect stepping stone from a past of coax distribution networks across to the world of IP distribution networks.
With EoC, you do not need to be an IT expert to create IP Networks. It also allows any Installer to continue to use the more familiar, and so much easier to fit, F type connectors.
Many Installers, have in the past been reluctant to move into the new IP based world, but as it becomes more and more essential to diversify their service offering to remain relevant and in some cases – simply in Business, EoC provides an essential pathway in to new revenue streams with many benefits to both the Installer and the Customer alike, not least of which are:
- Fibre Speeds with Coax Costs
- CAT6 Capacity – Coax Distance
- 1 Gigabit Network instantly on any Coax Network
- TV & Data both on the One Coax
- Wi-Fi Coverage to those hard-to-reach places
- Environmentally friendly by re-using the copper and plastic already in place
And most importantly of all to any Installer:
A better Streaming experience for their Customers = less call backs!
For those who have already diversified into installing IP Networks and Wi-Fi products, EoC is a very useful tool to have available in the toolkit. Perfect for those instances where other technologies are not suitable or for some reason are not deployable. The opportunities for its use are limited only by whether there is already a TV system in place and so can be offered to new markets such as:
- FTTB/H last leg extension – bridge the Gigabit gap from the Fibre to the Resident
- Hotels & Hospitality for Wi-Fi to the Room – Wi-Fi to the Guest, not just the Corridor!
- Campsites – High Speed Broadband into the Caravans or Lodges over their existing TV Distribution Coax
- Stadiums, Hospitals, University Campuses, Prisons – in fact, any Site or Building with an existing Coax Infrastructure
EoC, it really is, that simple!
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