Accelleran and Airhop explain Ultra Dense Small Cell Deployment

 The ever growing demand of capacity in densely populated urban areas leads quickly to the problem of managing overlaps in coverage and cell interferences. In this article published by AGL on their Issue nr. 14 (March 2017) our Director of Product Management Antonio Garcia explains the technical challenges of Ultra Dense Small Cell deployment and the performance obtained thanks to the eSON interference mitigation algorithm engineered by our partner Airhop and combined to our E1000 Series Small Cell.

Flexible, platform-agnostic, ultra-dense small cells working in concert with self-optimizing network technology help mobile network operators deliver higher data rates and an exceptional quality of experience to end users.

By ]oe Thorne and Antonio Garcia

The always-connected world in which we live fosters the need for high-quality, high-speed data services anywhere and everywhere: at home, at the office, in the subway, at the mall, at the concert venue or wherever our day takes us.

Mobile network operators worldwide are facing rapid growth in mobile user penetration, the number of connected devices in their networks, the amount of data consumption per user and the service level expectation of end users. Mobile network operators face increasing challenges to provide users with high quality services in a cost effective manner.

Addressing these challenges requires increasing the amount of radio frequency (RF) spectrum used or increasing the density of the mobile networks in capacity constrained urban, suburban and enterprise locations, or by extending coverage in coverage constrained rural and remote areas.

Small cells play a critical role in supporting these densification and coverage extension strategies. At the same time, 3.5 GHz spectrum offers as much as 400 megahertz of additional spectrum capacity and the opportunity to have a common worldwide mobile data band. Compared with lower frequency bands, the propagation characteristics of 3.5 GHz frequencies make them well suited for use in small cells.

As a result, mobile network operators use ultra dense small cell network deployments as an important tool for expanding services in key demand areas and for delivering both higher data rates and higher data capacity to support rich mobile content.

As coverage densification occurs, mobile network operators can effectively use higher frequency bands to deliver clusters of wireless capacity. Suitable bands include existing mobile network operator licensed spectrum above 1GHz and new mobile spectrum, with the 3.5 GHz band being a key example.

Even with the use of higher frequency bands, ultra dense small cell deployments introduce network service areas that are limited by interference from neighboring cells, as opposed to traditional macro deployments that are limited by propagation loss. Interference is a byproduct of frequency reuse and coverage overlap from adjacent cells, balancing the need for coverage and capacity.

Self Organizing Network (SON) technologies enable mobile network operators to effectively and efficiently address the interference among neighboring cells. SON technologies can also reduce network planning and automate network deployment and optimization to reduce the total cost of ownership for both high capacity and coverage areas.

Operators find network densification essential to meet the growing demand for high quality data services. To achieve consistently high quality service, ultra dense small cells must be coupled with SON technologies to meet the expanding end user requirements.

3.5 GHz Wireless Opportunity

RF spectrum at 3.5 GHz has traditionally been awarded mainly for point-to-point and fixed wireless access services and has already been deployed by more than 300 operators, most of which initially used WiMAX access technology. Since the advent of Long Term Evolution (LTE) technology and its growing ecosystem with global support and strong economies of scale, LTE, using the 3.5 GHz band, has become the 4G technology of choice compared with WiMAX technology.

In addition, worldwide regulatory bodies have prioritized enabling of mobile services at 3.5 GHz. In 2013, the European Conference of Postal and Telecommunication (CEPT) issued the technical conditions regarding spectrum harmonization for terrestrial wireless systems in the 3400—3800— MHz frequency band. This defined a mandatory time division duplex (TDD) band plan and a recommended TDD band plan for frequencies between the 3600 MHz and 3800 MHz, making regulatory conditions in Europe ideal for the use of the growing supply base of LTE TDD equipment.

Delegates to the 2015 International Telecommunications Union World Radiocommunication Conference achieved the global harmonisation of 3.5 GHz for mobile broadband. Japan, which has some of the most advanced telecommunications services, already has an ongoing full commercial deployment at 3.5 GHz. China is planning to award 3.5 GHz spectrum to complement its already extensive efforts in allocating spectrum for TDD technology.

At the beginning of 2016, the Federal Communications Commission issued the regulatory conditions and requirements for Citizens Broadband Radio Service (CBRS), an innovative licensing approach to 3550 —3700 MHz spectrum based on a database enabled spectrum access system that allows a three tiered model that protects federal incumbents while offering both licensed and shared access options to wireless providers. The creation of the CBRS Alliance in February 2016 and the official publication of the technical requirements for CBRS by the Wireless Innovation Forum at the beginning of December 2016 are providing the groundwork to enable CBRS in mass—volume commercial systems.

3.5 GHz Small Cell Systems

An example of an ultra dense small cell solution can be found from Accelleran, enabling low cost, carrier grade local area solutions for large scale small cell deployments across frequency division duplex (FDD) and TDD bands, specifically focused on new worldwide capacity bands at 3.5 GHz and including CBRS in the United States. The company uses its unique software and design capabilities to deliver cost effective, reliable solutions required for network densification. Accelleran is already delivering and trialling local area small cells in LTE band 42 (3400—3600 MHz) and band 43 (3600—3800 MHz) across the globe, targeting fixed wireless deployments in rural environments and in ultra dense urban environments. Accelleran will also deliver its CBRS specific local area small cell (3550—3700 MHz) to coincide with the expected mass volume deployment in the United States.

Real-time SON Technology

To address the challenges of ultra dense network deployments, AirHop Communication developed eSON, a state-of-the-art realtime SON solution with an interference management capability and with capacity and coverage optimization for heterogeneous networks.

eSON characterizes the wireless network radio environment in real time from the perspective of the end users to determine the cause, effect and necessary actions to coordinate and mitigate multiple cell interference in both frequency and time. With this unique capability, eSON can provide information back to the small cells to address network problems when and where they occur.

The results from commercial deployments of eSON have been extraordinary, producing double digit gains in spectral efficiency and data throughput improvements of more than 75 percent for users in ultra dense deployments.

The success of ultra dense small cell deployments hinges on both improved end user quality of experience and direct economic benefits for the mobile network operator. Real time SON is shown to deliver on both of these facets by improving the value of mobile network operator spectrum assets and increasing the data throughput capacity.

Real time SON is also a tool for the mobile network operator to deliver cost effective network densification by enabling a simple and scalable method for network planning and deployment. By mitigating the effect of coverage overlap through realtime interference management, mobile network operators are able to use template based planning for dense network deployments.

Through template based planning, a mobile network operator can establish targeted coverage and capacity obje ctives using basic small cell coverage patterns for the placement of each cell, relying on SON technology to manage the coverage overlap. The benefits include lower costs through the elimination of RF planning tools, higher reuse of existing power and backhaul services, accelerated time to deployment, and improved coverage and capacity for end users.

Deployment Scalability

Successful network densification also requires scalable technology for fast, cost effective deployment and ongoing maintenance. Together, Accelleran and AirHop deliver a deployment model that simplifies the required deployment technician skillset and automates configuration of each cell.

For example, Accelleran offers ultra-cost-optimized small cells that reduce mobile network operator capital spending to a minimum, enabling high volume ultra dense deployments. The Accelleran small cell minimal size and weight across its products, including the IP67-rated outdoor unit, reduce equipment visibility to a minimum, which can also be critical for many deployments. The integration of a flexible backhaul interface to make use of different wired and wireless backhaul technologies allows mobile network operators to have the toolset they require to use the best backhaul solution for each deployment. Additionally, the flexible operations, administration and maintenance management system of the Accelleran small cell software engine enables true heterogeneous network integration across different segments (residential, enterprise,   urban,   rural   and remote).

Operators supporting small cells across different segments can integrate the Accelleran small cell software engine into their core for any segment and be sure that it will behave the same across additional targeted small cell segments. This helps reduce the operating expense for operators wanting to integrate a heterogeneous network with their specific segment backhaul and management requirements.

In addition, the AirHop eSON flexible cloud based system provides high availability to manage Accelleran small cells through the mobile network. Scalability includes automated SON registration to the private cloud for immediate network optimization.

A scalable, ultra—dense small cell system has lower investment requirements, reaches the break even point faster and offers a higher return on investment in delivering wireless data services with a high quality of experience.



Mobile network operators through- out the globe face challenges when servicing the rapid acceleration in data consumption requirements and meeting the ever-increasing expectations for improved quality of ex- perience by end users. Ultra dense small cell deployments are a key approach to deploying high quality network capacity where the demand is most needed.

Applying LTE in high-frequency spectrum for ultra dense small cells spanning existing licensed cellular bands, mobilizing traditiona1 3.S-GHz hxed wireless access spectrum and supporting new innovative shared access spectrum paradigms, such as CBRS, fuel network densification. Introducing shared access schemes and different licensed and unlicensed mixes of spectrum open up opportunities for new market entrants and stakeholders beyond the traditional mobile network operators, such as over-the-top service providers, telecom infrastructure providers and municipalities. To balance coverage and throughput capacity requirements, ultra dense small cells require coverage overlap between neighbor cells in the cluster to eliminate coverage holes and ensure high speed access.

eSON advanced real time SON software goes beyond traditional network optimization. By dynamically characterizing the radio environment and enabling ultra-dense small cells to optimally share radio resources, eSON delivers unprecedented improvements in network capacity and deployment automation.

Accelleran’s cost-optimized, carrier-grade and mission critical grade flexible and platform agnostic ultra-dense small cells, working in concert with AirHop’s eSON, provide a powerful solution for mobile network operators to cost effectively deliver higher data rates and exceptional quality of experience to end users.


Joe Thome is a system integration aud test engineer at AirHop Communications. Antonio Garcia is founder and director of product management at Accelleran.

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