Friday, 18 June 2021

Cell-Site Construction And Evolution Strategies


We all agree that cell sites are complex beasts. The diagram above shows in a simple way all the tasks that may be necessary for cell site deployment. Late last year, ABI Research produced a whitepaper on "Global Cell-Site Construction And Evolution Strategies" that they made freely available here. Quoting the executive summary below:

5G networks are being rapidly deployed around the world with many of these networks working in parallel to existing legacy cellular technologies, such as 2G/3G and 4G, to provide higher data connections of 10X more throughput than 4G. 5G networks typically use high-frequency spectral resources (C-band and mmWave) and, according to the International Mobile Telecommunications 2020 (IMT-2020), the downlink and uplink peak data rate of a 5G network should be 20 Gigabits per Second (Gbps) and 10 Gbps, respectively, with downlink and uplink peak cell spectral efficiency of 30 bit/Second (s)/Hertz (Hz) and 15 bit/s/Hz, respectively. The use of higher frequency bands, which suffer from higher penetration loss and the continuous increase in requested data rates for end users, dictate the necessity of higher network availability and network capacity, which could be achieved through additional spectral resources and network densification. Many MNOs have already bought at auction spectrum for 5G deployment, but the network capacity can be maximized through network densification. Thus, the acquisition of cell site assets is critical for Mobile Network Operators (MNOs) for the effective performance of 5G networks.

These network requirements have brought huge challenges to MNOs, local governments, vendors, and System Integrators (SI), as some of those challenges are well-known unsolved issues evidenced by the deployment of legacy generations of cellular technologies and have become even more relevant now with the advent of 5G and the expected large-scale cell site densification.

These challenges range from the high cost associated with deploying network infrastructure at street level, to complex approval processes from local government, including lengthy and expensive site acquisition processes; lack of power availability; limited backhaul availability; lengthy planning application processes for street works or build works; limited space availability on premises and within street furniture; size and flexibility of existing cellular equipment that can fit the different rollout scenarios (e.g., smaller antennas to fit within wall-mounted small cell enclosures); lack of availability of underground space for the deployment of a new chamber and ducts; decluttering policies from local governments that can largely impact the deployment of 5G networks; and increasing tenancy fees for additional 5G equipment and increased power supply.

In response to this situation, there is some pressure on telecom equipment vendors to come forward with solutions that suit each rollout scenario. Improved physical features, such as smaller form factor antennas similar to the Wi-Fi Access Points (APs), lighter-weight and smaller Massive Multiple Input, Multiple Output (mMIMO) antennas, and an innovative variety of vendor equipment, backhaul, and reduced power consumption solutions will help MNOs address these challenges and stay ahead of the competition.

Finally, unlike previous generations of cellular technologies, policymakers, urban planners, and local governments have an important role to play, providing more flexible legislation that enable the rollout of network infrastructure at a faster speed by providing clear guidelines for easy access to the assets for the deployment of cellular infrastructure.

While many topics have been covered in the whitepaper, one of the issues I have closely experiences is the insufficient power for the new upgrades. Again, quoting from the whitepaper:

ENERGY

When deploying a cell site, the power requirement can typically be categorized as: 1) static power consumption, which is associated with the support system of a base station, and 2) dynamic power consumption, which is associated with the data traffic load. For a cell site, the amount of energy consumption varies depending on the amount of equipment and the number of frequency bands supported. Optimizing energy consumption can help operators lower their OPEX and achieve environmental goals.

CHALLENGES

Insufficient DC power capacity. Energy consumption is expected to increase with 5G deployments. New frequency bands and an increased number of equipment contribute to the this. Research on developed markets indicates that the maximum power consumption of a typical site supporting five bands could exceed 10 Kilowatts (kW). However, the reality is that about 30% of macrocell sites do not have a power supply that could support such power requirements. The common solution for energy expansion is adding more rectifiers or more energy cabinets. However, the equipment room or cabinet do not always have sufficient space for additional equipment. To cater to the increasing demand for energy, operators need to either find solutions that improve the existing equipment’s efficiency or construct new cabinets at sites. However, newly constructed cabinets also entail increased civil work and rental costs for operators.

Grid reconstruction. Grid power for the existing sites may be insufficient, especially due to the increase in power consumption with a 5G deployment. Such sites need grid modernization, which can be expensive and can greatly slow down the pace of a 5G deployment. Due to the process and construction requirements, the time to modernize the grid could be up to a year for each site.

Insufficient power backup. Operators need to meet the strict five nines or high availability of services. Ensuring business continuity is crucial for any operator. In times of prolonged bad weather or a power outage, grid and solar energy might not be available to power the cell site. Energy storage systems with lead-acid or lithium-ion batteries, for example, are required to mitigate the risk of a power outage. Most existing networks are still using lead-acid batteries, while the low-energy density, heavy weight, and big volume of a lead-acid battery make it difficult to do an expansion when deploying 5G.

High electricity cost. Another key challenge for operators is how to optimize energy efficiency, translating into good investments by operators. Relying solely on the electric grid could result in high energy expenditure, and the need to consider multiple energy resources. Traffic usage is also not constant throughout the day and varies depending on the location (e.g., city centers versus suburbs). How operators can manage the energy system intelligently and efficiently to reduce unnecessary waste becomes a core consideration.

Given the rapid development of 5G technology and an increasing host of service applications, computing is getting closer to users, with communication technologies and information technologies evolving toward converged Information and Communications Technology (ICT) architecture at an ever-faster pace. The increasing applications and computing required at the edge means that the power supply demand is expected to increase. Therefore, it is necessary to consider the amount of Alternating Current (AC)/Direct Current (DC) power supply needed at the cell site, as well as the number of equipment rooms that are required.

The paper goes on to describe the solutions. You can download the paper here.

If you have a favourite cell site issue do let us know in the comments.

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