Learnings

Outcomes

Outcomes of the LTE Connecting Futures project include the following: 

·        Creation of a Multi-Base Station Network

The key outcome of the project was the creation of a multi-vendor multi-base station LTE configuration, consisting of a three sector (cell) base station at Taunton and two single sector (cell) base stations at Elworthy Burrows and Bowdens Hill respectively. This was an important follow up to the single vendor, single base station LTE evaluation trial at Portishead, which mainly provided data on the fundamental design and capabilities of LTE and illustrated how such a communications network might be integrated into our infrastructure. No energy utility or sector service provider had carried out a multi-site, multi-vendor LTE trial with adjacent eNodeB’s in a ‘real’ energy environment. This project has demonstrated that a multi-base, multi-vendor network could be realised.

·        Radio Frequency Field & Drive Test Measurements Report

A report on Field Testing and Drive Tests has been produced. Field testing, within the geographic service areas of the three Base Stations, was designed to achieve the following: 

o   Verification of the accuracy of radio frequency coverage predictions;

o   Provide guidance in the location of test CPE sites;

o   Provide a reference source when examining the selection of best serving base station by each CPE site; and

o   Measure radio frequency noise levels, adjacent to CPE sites.

·        Penetration Test Report

A report on PEN Testing has been produced. This report covers the recommendations on the improvements to the operability and integration of the various LTE components.

·        High Level Design (HLD) document

A document detailing the structure and the assembly of the LTE configuration has been produced for the project. The document outlines the standard Nokia installation and specifications of the LTE solution. 

·        Training Materials

Online training materials have been developed for our staff. These are accessible using an approved passcode. 

·        CIRED Conference 2021

A technical paper on this project was written and accepted for presentation at the CIRED conference in September 2021.

Lessons Learnt

Lessons learnt as a result of the LTE Connecting Futures project are outlined below, and include:

·        Network Management 

Through the project, we were able to provide end to end services. However, no network management platform was instigated at the outset of the project, which made it difficult to implement IP/MPLS and QoS services across all devices. Whilst these service areas were possible, they were significantly more challenging to implement.

Operations, Administration and Maintenance (OAM) network management tools, and IP/MPLS services are deemed essential for large scale deployment.

·        Spectrum Availability

We were able to secure radio spectrum for the trial under OFCOM’s Test & Development license terms and conditions. LTE spectrum is governed by international agreements, as defined in the 3GPP (3rd Generation Partnership Project) suite of standards. In order to engage with Radio Access Network (RAN) vendors, spectrum licenses must be deployed in one of the 3GPP frequency bands. This frequency band must also be available in the region of deployment whilst also meeting the conditions as determined by OFCOM. Spectrum availability is challenging within the UK, and the project team had been fortunate enough in obtaining Test and Development licenses. These licenses had to be applied for on an annual basis and there was no guarantee that the project would be successful in procuring future licenses.

The procurement of radio spectrum for the LTE trial highlights the difficulties in obtaining spectrum for private LTE. It is paramount that the utilities, peer groups, lobbyists, regulatory bodies, and vested parties are united in procuring radio spectrum to meet the net zero carbon objectives of the utilities and the UK.

·        Security Vulnerabilities

We were able to perform PEN testing on the LTE system, which comprised a mixture of hardware and software components, with an increasing dependence on the software element. This emphasised the extreme importance in evaluating any security vulnerabilities which the software may inherently contain. The discovery of vulnerabilities in the software can have a detrimental effect on the project outcomes. Penetration or PEN testing is the de facto method for evaluating software before it is deployed into any system, and should be carried out as early in the project lifecycle as possible.

·        IP Planning

Nokia were instrumental in planning the IP network for the LTE RAN and core network, which also required strategic understanding of our IP network. Nokia were provided with a suite of IP addresses in which to build the LTE platform, which included the list of router connectivity for binding the system together.

Networks are increasingly deploying IP based solutions and whilst this simplifies the physical connectivity, it increases the complexity of network configurations. In a multi-vendor environment, understanding the co-existence and integration of the various components of the system should be planned at the early stage of the project. It’s also necessary to recognise that LTE equipment can be sourced from multiple vendors, and IP planning is fundamental in accommodating the different configurations required for each application.

A single vendor solution simplifies the IP planning and system configuration. However, there is a risk that the scope of the project becomes biased to a solution favoured by a particular vendor.

A key learning which developed from this project was the importance of a detailed understanding of the needs of both the system being implemented, and what our Data Core Network (DCN) actually supported. A typical example was Nokia’s efforts in deploying an IP/MPLS topology, where we had to change the system to meet the needs of what we can currently support, which was not IP/MPLS based.

We were also able to produce an overview of an IP addressing scheme to facilitate a future ‘live’ LTE deployment that avoids ambiguity in system configuration and promotes healthy network planning.  

·        Remote Access 

Consideration should be given to deploy remote access for support teams at the outset of any project. The response to remote access for this project was reactive in the light of COVID-19, but the learning is that this has a significant advantage to the project, especially whilst the system is being developed, and where there are specific issues which require ‘expertise’ to rectify. Planning for future projects should include full contingency for remote access for management and configuration.

·        RAN Installation

The hybrid cable development may not necessarily be the optimal solution when installing RAN base stations (eNodeB’s). Separate fibre and DC cables may be a simpler and more cost-effective solution. We will be reviewing the installation of the hybrid cables with our installation team as part of the learning process.

·        400 MHz Frequency Band

The radio equipment in this project was able to operate in the 400 MHz (UHF) frequency range. This spectrum band is commonly termed the ‘Sweet-Spot’ for critical telecommunications and is always in great demand for critical applications due to its capability to provide good coverage, and capacity with a reasonable data payload and relatively compact antenna sizes.

·        Bench RF Measurements

Within bench measurements, the possibility of signal leakage and equipment cross coupling should be considered, and the impact on testing fully understood. Separating equipment and using screened enclosures offers mitigation. Carefully calibrated, conducted paths are more preferable than radiated paths.

·        Field RF Measurements

The use of a dedicated test receiver that was able to identify and report parameters individually from each eNodeB, was essential in checking and understanding RF performance. 

·        Connectivity

LTE provides the transport medium for data and voice services such as SCADA, mobile data, mobile voice, mobile video, fixed voice and Closed Circuit Television (CCTV) etc. This trial has been able to assess the capability of LTE to connect these services to our network. 

·        LTE Core Replacement

As a result of Penetration Testing, Nokia replaced the Micro-core Network (MCN) variant of the LTE Core with their current release called Compact Mobility Unit (CMU+), which included the latest patches and firmware. The original MCN Core was a legacy Nokia product. The CMU+ was intended to mitigate the findings in the PEN tests.

·        License Management

We were able to maintain a register of software and spectrum license expiration dates in order to prevent system downtime due to inadvertent system shutdowns. Shutdowns are difficult to fix in emergency situations, and can incur significant delays in restoration due to the requirement to conduct diagnosis and rectification processes.

·        Band 87 handsets

We were able to migrate all existing Band 126 CPE’s to the 3GPP standardised Band 87.       

Training
Nokia had provided access to an LTE training programme where our staff were able to work through the various aspects of the LTE system at their own pace. On site and remote training had also been carried out during active system configurations. 

It became clear during the course of the project that ‘Hands on’ training was the most effective form. 

As this was a relatively new technology to us, there was a large element of learning and discovery. Nokia was also subjected to an element of learning, especially after the deployment of the new EPC, as some aspects of the deployment was also new to the key personnel assigned to the project. This created a lag in the teams’ ability to progress with the project quickly, but did not subsequently have a significant impact on the overall project.

Whilst this is an excellent way to fully understand a system, it slows the progress to a degree. It might have been preferable for an ‘overview’ training course to be conducted early in the project to gain a basic understanding of the system, supported by the ‘hands on’ training which followed.