Fixed Wireless Access (FWA) market has experienced tremendous growth based on the soaring demand for ultra-broadband services, coming from residential and business subscriber segments. To satisfy the demand, Communication Service Providers (CSPs) are now exploiting solutions that utilize the worldwide allocation of harmonized frequency bands in the millimeter wave (mmWave) spectrum @ 24/26/28GHz (5G FR2 n257, n258).
From the physical resources perspective, the opportunity of using wider channels at mmWave bands makes these parts of spectrum very attractive in serving both coverage and capacity. Ηowever due to the intensive frequency reuse required, FWA networks are intrinsically prone to interference. From the business perspective, the need to achieve market penetration and deploy at an accelerated pace, requires insightful decision-making based on detailed technical analyses.
This article highlights the associated challenges and indicates how these can be managed by facilitating the appropriate RF Planning techniques through-out the entire FWA lifecycle in order to satisfy subscriber needs, fulﬁll business objectives and yield considerable re-turns to investors.
Best area coverage and high bandwidth per customer are the key business objectives for a successful FWA network. In order to fulﬁl them, CSPs must optimize their processes throughout the FWA network lifecycle phases, over which, RF Planning’s contribution is crucial.
Starting from the FWA business plan formulation, RF planning needs to be utilized for technical dimensioning calculations including but not limited to maximum service range, number of customers per HUB deﬁnition and HUB conﬁguration, so that attractive service packages can be oﬀered to target customers in a cost-eﬃcient manner.
In this regard, several conditions have to be examined, such as available spectrum resources, channelization restrictions, customer data rates, morphology as well as regulations in force (e.g. use of certain antenna diameters). All these available options are to be examined by the planning team that will provide performance analyses for a variety of scenarios usually within strict timeline.
Firstly, the area of interest with the potential end customers is identiﬁed. In addition, the candidate HUB locations with telecom infrastructure capability are considered. RF Planning's main focus at this phase is the selection of the proper location to build the HUBs so as to best serve the area. Usually HUBs selection is a challenging process where visibility conditions, installation and cost limitations, as well as network topology (i.e. HUBs optimum distribution) and possible network evolution have to be analyzed in detail and make the optimum decision.
In FWA network, RF Planning is not limited to the location selection, the real challenge is to ﬁnd the frequency and polarization reuse pattern that mitigates the interference levels from nearby HUBs to the potential customers of the new HUB and vice versa. Taking into account that in the majority of the real life cases, the exact customers locations are not known during this phase, the only way to ﬁnd out the optimum frequency and polarization reuse scheme is to perform area coverage and interference simulations and compare diﬀerent scenarios so as to achieve the highest Phy modes distributions in the service areas.
HUBs implementation sub-phase is typically the most easy-going period from planning point of view given that the every HUB has been designed as part of a network and not as a “stand-alone” point of access. However the real challenge here is to be conﬁdent that the plan has been followed so as to avoid Terminal Station installation failures and unnecessary revisits in customer premises. The veriﬁcation of the HUBs implementation is really important and can take place either with ﬁeld testing right after the finalization of a HUB installation or by taking advantage of the first customer that joins a HUB.
Apart from being confident about the installation of the HUBs and in order to exploit the spectrum resources and maximize performance, optimum Terminal Station installation is mandatory, too. For this purpose a detailed installation plan is derived. The installation work orders include specific KPIs to meet when the Terminal Station is activated and a list of alternative HUBs to be used in case a connection to the primary one cannot be established. The main objective is to maximize the network performance, while the rollout is performed very quickly, avoiding possible field revisits.
Optimization phase The scope at this phase is to perform optimization actions while eliminating down-time in either corrective interventions for dealing with performance degradation or deliberate actions for network evolution. A reliable as-built information database together with actual historical performance data has to be used to feed the analyses of the cases under investigation. This pool of data can be formulated by using various tools that are in place, after extracting and homogenizing the available data-sets. The challenge is to exploit information from a variety of fragmented sources within reasonable time-frame.
The challenges highlighted across the network lifecycle phases need to be addressed in order to serve the purpose of building and operating a reliable and efficient FWA network assuring the best quality for the end subscriber. Leveraging the licensed FWA comparative advantages of utilizing interference-free bands of the spectrum and without dealing with uncertainties of unlicensed alternatives, QoS-enabled services can be designed and delivered with unmatched precision, given the following factors are met:
HUBs designed as independent entities or even installed in an ad-hoc basis have always been proven to be the main reasons for a network to fail. Badly designed networks cannot expand and a radical reorganization of the entire HUBs and customers base is mandatory, imposing numerous and costly ﬁeld actions. Careful planning is needed with examination of all possible scenarios so as to avoid those obstacles.
On the other hand, a well-designed network may suﬀer from improper installations of HUBs, resulting to customer connection failures till the origin of the problem is identiﬁed and resolved. Improper installations with incomplete communication of installation details or proofs of proper installation may result to timeconsuming processes trying to identify the issue with repeatable site visits. To prevent such situations Interworking of Planning & Physical Views is needed.
Maintaining installation details and following the installa-tion processes had always been the greatest challenge in the deployment of huge networks. The aforementioned In-terworking of Planning & Physical Views, further enhanced with a global information database accessible by all involved parties, along with high level of automation for repetitive and/or time consuming tasks will provide the tools needed to meet these challenges.
A quite common situation is to end up with unbalanced capacity load between neighbor sectors. This may happen either due to lack of a plan for the Terminal Stations installation or due to ﬁeld conditions that led to the assignment of many Terminals to a particular HUB. For example, a HUB installed on high elevation will be selected despite the fact that alternatives with better performance are available. Usually HUBs installed on easily distinguishable locations are accommodating a high number of subscribers even though their performance may be low. On the other hand, HUBs that are not easily distinguished due to buildings clutter and vegetation are usually underutilized. For this purpose smart tools, like Best Server Analysis (ﬁnd the best HUB according to several KPIs), need to be utilized to identify the best option.
The uni|MS™ Radio Planner is a powerful Radio Network design tool supplying all the necessary facilities of Geo Data, Radios & Antennas Equipment, Frequency Channels, Waveguides and Couplers libraries, ITU and North-American design standards and climatic maps.
The rich variety of Analyses (Interference, Link Performance, Diﬀraction Loss, Reﬂections, Antenna Height Adjustment, Coverage Maps, and Capacity Analysis) oﬀered in Reports and in the Map View can guide appropriately the Radio Planners for optimum radio design results.
The intuitive uni|MS™ User Interface, the import/export functionalities along with smart algorithms for time-consuming processes facilitate the design alterations to be analyzed for the performance quantiﬁcation of various scenarios.
Coverage maps algorithms developed to serve FWA networks simulations and not mobile network simulations - as the majority of the available tools oﬀering coverage functionalities - facilitate the HUBs design and optimization processes, while in collaboration with the smart algorithms developed to optimize the processes of properly adjusting the Azimuth and Tilt and Frequency Reuse of FWA sectors to cover certain area or customers assists the Radio Planning Engineers to provide reliable data for the network design.
For the Roll-out phase the powerful Best Server Analysis providing a complete capacity and coverage prioritization and KPIs fulﬁllment analysis boosts the Radio Planning Engineers' eﬃciency to analyze service requests and provide detailed guidance for the ﬁeld actions so as to prevent unacceptable installations and costly customers' revisits.
The capacity analysis engine provides an adapting environment depending on the technology speciﬁcation (time or capacity sharing) while for Intracom Telecom products a complete simulation of the resources allocation and the sector utilization is provided.
Interworking of Planning & Physical Views
The uni|MS™ Radio Planner can be facilitated as a standalone tool for RF Planning activities or it can leverage the network management application modules of the uni|MS™ platform for a closed-loop approach of the entire FWA network lifecycle activities, performed from a single User Interface.
uni|MS™ Radio Planner is seamlessly interworking with the other uni|MS™ platform application modules oﬀering the great advantage of homogeneous data structure for Planning and Operational data, such as Sites naming convention, coordinates, installation/workorder details/actual service provisioning that can be accessed from all CSP departments that saves time with no error-prone manual data transformation compared to using various tools. Decision-making is eﬃcient and based on data which is always up to date at a closed loop fashion. Consequently, accurate network evolution with physical network modelled in the RF planning tool, because Planners always have access on ac-tual physical data.
Design and installation inconsistencies are directly inspected oﬀering the advantage of proactive optimization rather than being reactive and accelerated roll-out is achieved with automated Acceptance testing and audit activities avoiding site revisits.
Operational & Business Automations via API
The network lifecycle management concept, uniquely of-fered by the uni|MS™ platform, bridges the communication gap between Planners, Operators and Field Engineers accelerating insightful decision-making across the CSP organization. Elevating this concept, operational and business automations are oﬀered via seamless integration with existing OSS/BSS infrastructure or via Network Lifecycle Automa-tion Apps eliminating error-prone human involvement.
For operational automation, consider a case where the as-built information for Sites & HUBs is either not available in the uni|MS™ Radio Planner or a third-party tool has been utilized for Sites & HUBs planning. This information, critical for Terminal Station planning, can easily be inserted in a Planning Project via the uni|MS™ Rest API and can be created, modiﬁed and deleted.
For business automation, consider FWA customer accept-ance in a way similar to xDSL, avoiding the lengthy evalua-tion process where RF planners would need to be engaged. Instead you can have your self-care portal to initiate the request and a uni|MS™ REST API providing the answer, making sure capacity and coverage KPIs are met based on smart planning algorithms that indicate the Best sector, the Terminal Station installation height and Antenna type, among other signiﬁcant information at a touch of a button, while your RF Planning Expert could focus on supervising the au-tomation and validating the relevant parameters.