Thursday, 26 November 2020

NTT Docomo's 5G RAN Infrastructure

We looked at NTT Docomo's 5G Journey and 5G Network Deployment details recently here. In this post we will look at the 5G Infrastructure that Docomo is using in their network. It is detailed in their latest Technical Journal here. In this post we will look at the infrastructure part only.


The 5G network configuration is shown in Figure 4. With a view to 5G service development, NTT DOCOMO developed a Central Unit (CU) that consolidates the Base Band (BB) signal processing section supporting 5G, extended existing BB processing equipment known as high-density Base station Digital processing Equipment (BDE), and developed a 5G Radio Unit (RU) having signal transmit / receive functions. Furthermore, to have a single CU accommodate many RUs, NTT DOCOMO developed a 5G version of the FrontHaul Multiplexer (FHM) deployed in LTE. Each of these three types of equipment is described below.

1) CU
(a) Development concept: With the aim of achieving a smooth rollout of 5G services, NTT DOCOMO developed a CU that enables area construction without having to replace existing equipment while minimizing the construction period and facility investment. This was accomplished by making maximum use of the existing high-density BDE that performs BB signal processing, replacing some of the cards of the high-density BDE, and upgrading the software to support 5G.

(b) CU basic specifications: An external view of this CU is shown in Photo 1. This equipment has the features described below (Table 3). As described above, this equipment enables 5G-supporting functions by replacing some of the cards of the existing high-density BDE. In addition, future software upgrades will load both software supporting conventional 3G/LTE/LTE-Advanced and software supporting 5G. This will enable the construction of a network supporting three generations of mobile communications from 3G to 5G with a single CU.

The existing LTE-Advanced system employs advanced Centralized RAN (C-RAN) architecture proposed by NTT DOCOMO. This architecture is also supported in 5G with the connection between CU and RUs made via the fronthaul. Standardization of this fronthaul was promoted at the Open RAN (O-RAN) Alliance jointly established in February 2018 by five operators including NTT DOCOMO.  Since the launch of 5G services, the fronthaul in the NTT DOCOMO network was made to conform to these O-RAN fronthaul specifications that enable interoperability between different vendors, and any CU and RU that conform to these specifications can be interconnected regardless of vendor. The specifications for inter-connecting base-station equipment also con-form to these O-RAN specifications, which means that a multi-vendor connection can be made between a CU supporting 5G and a high-density BDE supporting LTE-Advanced. This enables NTT DOCOMO to deploy a CU regardless of the vendor of the existing high-density BDE and to quickly and flexibly roll out service areas where needed while making best use of existing assets. In addition, six or more fronthaul connections can be made per CU and the destination RU of each fronthaul connection can be se-lected. Since 5G supports wideband trans-mission beyond that of LTE-Advanced, the fronthaul transmission rate has been extend-ed from the existing peak rate of 9.8 Gbps to a peak rate of 25 Gbps while achieving a CU/RU optical distance equivalent to that of the existing high-density BDE.

2) RU
(a) Development concept: To facilitate flexible area construction right from the launch of 5G services, NTT DOCOMO developed the low-power Small Radio Unit (SRU) as the RU for small cells and developed, in particular, separate SRUs for each of the 3.7 GHz, 4.5 GHz, and 28 GHz frequency bands provided at the launch of the 5G pre-commercial service in September 2019. Furthermore, with an eye to early expansion of the 5G service area, NTT DOCOMO developed the Regular power Radio Unit (RRU) as the RU for macrocells to enable the efficient creation of service areas in suburbs and elsewhere.

A key 5G function is beamforming that aims to reduce interference with other cells and thereby improve the user’s quality of experience. To support this function, NTT DOCOMO developed a unit that integrates the antenna and 5G radio section (antenna-integrated RU). It also developed a unit that separates the antenna and 5G radio section (antenna-separated RU) to enable an RU to be placed alongside existing 3G/LTE/LTE-Advanced Radio Equipment (RE) and facilitate flexible installation even for locations with limited space or other constraints.

(b) SRU basic specifications: As described above, NTT DOCOMO developed the SRU to enable flexible construction of 5G service areas. It developed, in particular, antenna-integrated SRUs to support each of the 3.7 GHz, 4.5 GHz, and 28 GHz frequency bands provided at the launch of the 5G pre-commercial service and antenna-separated SRUs to support each of the 3.7 GHz and 4.5 GHz frequency bands (Photo 2). These two types of SRUs have the following features (Table 4).

The antenna-integrated RU is equipped with an antenna panel to implement the beamforming function. In the 3.7 GHz and 4.5 GHz bands, specifications call for a maximum of 8 beams, and in the 28 GHz band, for a maximum of 64 beams. An area may be formed with the number of transmit/receive beams tailored to the TDD Config used by NTT DOCOMO. In addition, the number of transmit/receive branches is 4 for the 3.7 GHz and 4.5 GHz bands and 2 for the 28 GHz band, and MIMO transmission/reception can be performed with a maximum of 4 layers for the former bands and a maximum of 2 layers for the latter band.

The antenna-separated SRU is configured with only the radio as in conventional RE to save space and facilitate installation. With this type of SRU, the antenna may be installed at a different location. Moreover, compared to the antenna-integrated SRU operating in the same frequency band, the antenna-separated SRU reduces equipment volume to 6.5ℓ or less. The antenna-separated SRU does not support the beamforming function, but features four transmit/receive branches the same as the antenna-integrated SRU for the same frequency band.

(c) RRU basic specifications: The RRU was developed in conjunction with the 5G service rollout as high-power equipment compared with the SRU with a view to early expansion of the 5G service area (Photo 3). This type of equipment has the following features (Table 5).


Compared with existing Remote Radio Equipment (RRE) for macrocells, the volume of RRU equipment tends to be larger to support 5G broadband, but in view of the latest electronic device trends, NTT DOCOMO took the lead in developing and deploying an antenna-separated RRU that could save space and reduce weight. Maximum transmission power is 36.3 W/100 MHz/branch taking the radius of a macrocell area into account. The RRU features four transmit/receive branches and achieves the same number of MIMO transmission/reception layers as the antenna-separated SRU.
NTT DOCOMO also plans to deploy an antenna-integrated RRU at a later date. The plan here is to construct 5G service areas in a flexible manner making best use of each of these models while taking installation location and other factors into account.

3) 5G FHM
The 5G FHM is equipment having a multiplexing function for splitting and combining a maximum of 12 radio signals on the fronthaul. It was developed in conjunction with the 5G service rollout the same as RRU (Photo 4).
If no 5G FHM is being used, each RU is accommodated as one cell, but when using a 5G FHM, a maximum of 12 RUs can be accommodated as one cell in a CU. At the launch of 5G services, this meant that more RUs could be accommodated in a single CU when forming a service area in a location having low required radio capacity (Figure 5). Additionally, since all RUs transmit and receive radio signals of the same cell, the 5G FHM can inhibit inter-RU interference and the occurrence of Hand-Over (HO) control between RUs as in the conventional FHM. Furthermore, the 5G FHM supports all of the 5G frequency bands, that is, the 3.7 GHz, 4.5 GHz, and 28 GHz bands, which means that service areas can be constructed in a flexible manner applying each of these frequency bands as needed.

All the fronthaul and other interfaces that Docomo used in their network was based on O-RAN alliance specifications. In a future post, we will look at some of the details.

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Thursday, 19 November 2020

Telia Norway Launches 5G Fixed-Wireless Access (FWA)

Telia Norge (Norway) claims to have become the first of the country’s CSP to introduce a Fixed-Wireless Access (FWA) 5G service. Announcing the product development in a press release, the operator said:

Telia Norway is challenging the broadband market again and is the first in the country to offer wireless broadband (FWA) with 5G. New and existing customers now have access to very high and stable internet speeds in the home delivered over Telia's super-fast 5G network. 

- We are very proud to be the first in Norway with wireless broadband with 5G. We are experiencing great demand for wireless broadband across the country, and are confident that the 5G product will be very attractive to many, especially copper customers who now need new internet, says Pål Rune Kaalen, head of the private market in Telia Norway. - We are starting the rollout in Trondheim, and will gradually open for ordering based on where in the country we have 5G coverage, and where we experience great interest from customers. In areas of great interest, we will actively prioritize the development of 5G.

5G fiber speeds

With 5G wireless broadband, you as a customer get very high and stable internet speeds at home delivered over Telia's super-fast 5G network. Initially, download speeds of 100, 200 and 300 Mbps are offered, which are the fastest speeds on the market today. In the long run, Telia will deliver even higher speeds on the product. All you need to use wireless broadband is a small outdoor antenna receiver and an indoor router, which is delivered when the product is installed in your home. The internet signals come from the nearest base station.

- We are committed to ensuring the best possible customer experience, and therefore the product comes with a dedicated outdoor antenna receiver and a market-leading Wi-Fi 6 router, which provides maximum speeds and optimal stability when surfing, streaming and playing, says Kaalen. - Furthermore, we always ensure a professional installation in your home, and since the internet signals come from a base station, you avoid extensive digging as with fiber, which provides a cheap, fast and not least flexible installation.

Existing customers who currently have 4G wireless broadband will easily be able to upgrade to 5G by replacing the antenna receiver outdoors. The wireless Wi-Fi 6 router is already ready for the new solution.

Half the population of 5G next year

Telia has high speed in the development of its national 5G network, and has so far opened the network in Oslo, Bergen, Trondheim and Lillestrøm. Wireless broadband with 5G will be offered continuously in areas that have and receive 5G coverage. Telia's 5G development is taking place area by area throughout the country, and during the next year, half the population will have access to 5G where they live. Telia will be the first with a nationwide 5G network by the end of 2023.

- More and more people will have the opportunity to order wireless broadband with 5G in the time ahead, and as a customer it pays to choose Telia, as we are at the forefront of 5G development in this country while delivering the fastest internet speeds, says Kaalen. - At the same time, we are working hard to be able to deliver a leading TV offer through wireless broadband, so we will come up with more exciting news soon.

Telia wireless broadband with 5G is offered with download speeds of 100, 200 and 300 Mbps, with 50 Mbps in common upload speeds. The fixed monthly price is NOK 699, 799 and 999, respectively, and the installation cost is NOK 3,499 for new and existing customers. The product comes with a dedicated outdoor antenna receiver and market-leading Wi-Fi 6 routers - both from the renowned network manufacturer Zyxel. 

Their Wireless Broadband page provides more information on the different types of broadband and the price plans. 

We have explained FWA in our tutorial here. The tutorial video is embedded below.

Worth noting that the 5G network by Telia Norway is from Ericsson.

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Thursday, 12 November 2020

TIM and INWIT to deploy small cells in Italy


INWIT (Italian Wireless Infrastructures) is currently Italy’s major Tower Operator providing widespread coverage throughout the country, hosting the transmission equipment for all main national operators. Back in March, INWIT became the largest tower company in Italy after purchase, by INWIT, of a minority stake of 43.4% of the share capital of Vodafone Towers and for the subsequent merger of the latter into INWIT. 

In a press release last week, TIM and INWIT announced:

TIM and INWIT started a collaboration to deploy small cells in Italy’s major cities in order to make the mobile phone signal more performing and support the development of 5G.

The collaboration will begin in Milan and Genoa where it is expected to install about 100 small cells and will continue in other cities and places with high traffic density, as the support of micro-antennas will be needed to achieve an optimal 5G network.

Small cells are small antennas built and used to integrate the signal that is guaranteed by the systems placed on traditional towers. Despite the spread throughout the territory of traditional macro towers (INWIT has over 22,000 sites) and despite the fact that their number is growing to meet the ever-increasing demand for mobile connections by customers, more and more small cells systems capable of increasing the quality of the signal will be developed in large urban centers.

Small cells play a fundamental role, especially for the development and perfect functioning of 5G and its services. Indeed, this new technology features low latency (a minimum delay between the request and the reception of information) and a data transmission speed ten times faster than previous systems. In order to maintain these characteristics and to allow all connected devices to operate at their best, the quality of the 5G radio signal must always be optimal.

TIM and INWIT have already experimented underground solutions in several municipalities, such as small cells that are inserted in manholes under the road surface that, especially in venues with a remarkable artistic value or in ancient towns, by no means alter the artistic integrity.

It is interesting to see that there there has already been some experimentation with small cells in manhole covers. We have written extensively about it and you can find some of the posts in the references below.

It is also important to point out that in the announcement above, it says: "Small cells are small antennas built and used to integrate the signal that is guaranteed by the systems placed on traditional towers. "

Small Cells definition can be quite loose, so not sure what they mean by this. In the USA, outdoor Small cells is generally used to refer to Remote Radio Heads (RRHs) rather than an all in one unit. It can mean that.

Small cell forum also clarified the definition of 5G small cell that is available here.

TelecomTV in their newsletter on Monday said: "The team at TIM (Telecom Italia) tells us that the small 5G RAN nodes being deployed in partnership with towers firm INWIT will be for TIM’s use only, and that technology from multiple vendors will be used, though the initial rollouts in Milan and Genoa will use small cells supplied by Ericsson. "

Hopefully we will find out more details in the near future.

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Thursday, 5 November 2020

OpenSoftHaul - Disaggregated White Box Solution from TIP

Telecom Infra Project (TIP) is on a mission to disaggregate all network components so backhaul is no exception. OpenSoftHaul (OSH) is a wireless backhaul transport solution, adopting the principles of an open and disaggregated architecture as can be seen in the picture above. A detailed specification is available here. 

Axiata, Deutsche Telekom, MTN, Telefónica, and TIM Brasil have been coordinating a joint RFI to assess the global technology landscape for building the first-in-the-world service providers-driven Open and Disaggregated wireless backhaul solutions as a part of the Telecom Infra Project’s Wireless Backhaul Project Group (WBH PG). A press release on their website said:

The industry’s leading hardware and software technology providers have been asked to participate in the RFI, share information on their current technical capabilities, and supported features to measure the level of compliance and their plans to build solutions that fulfill the OpenSoftHaul (OSH) technical requirements developed in TIP.

“The Wireless Backhaul Project Group is a multi-operator led program. By having worked together since the ideation phase, we decided to execute a joint RFI to maximize the demand signal to the industry and the technology makers to accelerate innovation with solutions that will promote deployment flexibility and will lead the way in automation and operational efficiency,” said Dimitris Siomos, Principal Network Expert at Deutsche Telekom Group.

Multiple technology providers have answered the RFI, focusing on one or multiple components of the wireless backhaul system and have gone through a detailed technical evaluation with the operators of all RFI answers based on the following criteria: solution architecture, openness, functionality, scalability, availability & solution roadmap.

Following the technical evaluation, the operators have identified the following best positioned suppliers (in no particular order) :

  • For HW ODU : Aviat Networks, Ceragon, Intracom Telecom & SIAE Microelectronica
  • For HW IDU : Alpha Networks, Ceragon, Delta, Edgecore Networks & UfiSpace
  • For NOS SW : Aviat Networks, Ceragon, Adva Optical Networking, IP Infusion, Altran, Exaware & Infinera

The technical specifications document, represents the alignment of the operators on the transformation needed in the wireless backhaul technology. Together, they have defined the key aspects of an OpenSoftHaul product, including performance, openness, standardized interfaces, scalability, flexibility of deployment, operation, automation, and total cost of ownership.Earlier this year, the WBH PG published the technical specifications document of the OpenSoftHaul (OSH) solution.

The technical specifications document, represents the alignment of the operators on the transformation needed in the wireless backhaul technology. Together, they have defined the key aspects of an OpenSoftHaul product, including performance, openness, standardized interfaces, scalability, flexibility of deployment, operation, automation, and total cost of ownership.

The OpenSoftHaul RFI announcement webinar also provides a lot more details on OSH. It is embedded below.

OpenSoftHaul RFI Announcement from Telecom Infra Project on Vimeo.

Disaggregation is expected to play a huge role in future networks where operators are looking for plug and play components from multiple vendors to reduce dependency on any single vendor as well as reduce the TCO. We will start seeing some major rollouts of this in the next couple of years.

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