HetNet design and performance planning

Tools enable people to perform tasks they could not otherwise do, or do them faster, more accurately or at lower cost. RF planning  and  performance prediction tools work by packaging up expertise from a range of disciplines and putting them into the hands of designers, planners and operations teams to give them the ability to understand, manage and monetise the mobile connectivity experience delivered by HetNets.

iBuildNet by Ranplan represents a new generation of holistic planning tools, fundamentally designed around the RF prediction needs throughout the design, deploy, operate and upgrade lifecycle of networks. It is capable of modelling key components of the HetNet and their interactions: indoor/outdoor, macro, small cell, DAS and backhaul, 2G, 3G, 4G and Wi-Fi technologies. Interfaces have been designed and customised to integrate into different user groups’ workflows, ensuring it can accurately model their technologies, environments and networks, and tailor the form of output to suit different customer needs. The use of a common platform throughout the lifecycle enables reuse of data assets from different groups, helping reduce overall effort and cost, and  improving the accuracy of the later stages of network planning.

Advanced Indoor and Outdoor Modelling

The foundation of RF planning is a model of the physical environment: the shape of the terrain and what was once considered ‘clutter’ for outdoor macro coverage – i.e. the buildings where the vast majority of traffic is now consumed. iBuildNet simultaneously models both indoor and outdoor environments and propagation interactions between them. In constructing models of large areas, in-building details can be added where needed to provide accurate indoor performance analysis. It can also be left out where just a quick initial view of only the outdoor area  is needed.

Large metropolitan areas are modelled starting with the outdoor environment. Wide area characteristics of terrain, buildings and other ‘clutter’ can be automatically captured from a range of formats and iBuildNet’s 3D capability is used to visualise and refine the model.

Key features of iBuildNet’s wide area modelling capability include:

  • 3D and 2D visualisation of terrain, building vectors and clutter.
  • Compatibility with a range of GIS formats, including planet, mid, mif, etc.
  • A database of propagation characteristics for different clutter types including building materials, forest, green spaces, rivers etc. Default transmission, reflection and diffraction losses can later be calibrated against measurements.
  • Integration with Google Earth, assisting verification of relative locations of buildings .
  • Wide area modelling of up to 40km2, sufficient for most HetNet deployments.
  • Seamless integration of outdoor and indoor environments. Where analysis of in building systems and performance is needed, external building vectors can be replaced with detailed 3D in-building models.

Propagation Engine

iBuildNet uses Ranplan’s proprietary radio propagation engine for fast and accurate system performance evaluations including path loss, signal level, SINR, cell overlap area and best server maps. The Intelligent Ray Launching  Algorithm (IRLA) is based on ray launching and tracing techniques, which in addition to accurate prediction of path loss and coverage, enables the evaluation of more advanced channel characteristics such as the Angle of Arrival (AoA), Angle of Departure (AoD) and Power Delay Profiles (PDP). These angle and delay spread analyses are useful in the optimisation of MIMO antenna configuration and alignment.

 

Key features of the iBuildNet propagation engine include:

  • Fast and accurate propagation prediction:
    • Computation of 2 million receiving points’ signal strengths and multipath information in 2 minutes  on a standard PC
    • Signal strength prediction within 6dB RMSE for indoor and 8dB RMSE for outdoor scenarios.
    • Accuracy has been verified by numerous measurement campaigns with some of the world’s largest network vendors and operators and through academic research.
  • 300MHz to 65GHz carrier frequencies covered
  • Indoor, outdoor, indoor to outdoor and outdoor to indoor scenarios.
  • APIs to enable further processing of propagation and channel data.
  • Supports all multipath parameters specified in 3GPP TR25.99627 for MIMO simulations.
  • Supports massive MIMO and FD-MIMO modelling.
  • Comprehensive materials database of RF properties for frequencies up to 65GHz.
  • Runs on PCs or distributed/parallel computing environments.

iBuildNet also supports empirical/semi-empirical models such as COST-231-HATA, COST-231-Walsh-Ikegami, SPM, multi-wall and WINNER. These may be used for comparison and alignment with other analysis.

Coverage Prediction and Not-Spot Identification

The combination of physical model, RAN site locations and configurations with propagation prediction yields the coverage of the HetNet– the downlink signal strengths available to user terminals in any given location. Although high signal strength does not necessarily mean a good user experience, a lack of any signal certainly indicates a service outage, or ‘not spot’, which planners must avoid. iBuildNet overlays coverage onto the 3D outdoor and indoor areas. Where detailed indoor areas have been modelled, the indoor coverage on each floor is included.

Prediction accuracy has been verified by numerous measurement campaigns with some of the world’s largest mobile operators and network vendors.

Overall, we find accuracy to be RMSE of 6dB for indoor prediction and 8dB for outdoor prediction.

WNS and Traffic Modelling

Whilst coverage is essential for mobile services, signal strength analysis alone does not reveal whether consumers will experience good network performance. For this, interference and loading must also be taken into account. In today’s capacity limited networks, there are significant coverage overlaps between different elements of the HetNet. Best server mapping reveals the catchment area of any one cell site or sector antenna. Interference analysis then calculates the signal quality in terms of the wanted signal to noise ratios plus interference from all other sites (SINR). In evaluating SINR, iBuildNet’s Wireless Network Simulator module (WNS) also takes into account the interference co-ordination mechanisms such as eICIC or CoMP.

End user data rates are determined by the combination of signal quality and network loading. iBuildNet simulates different traffic loading conditions by populating the network with a set of UEs consuming a mix of services. This reveals how user experience and network performance vary under load and helps identify areas for network upgrades.

Key features of WNS include:

  • Uplink and downlink simulation of LTE, HSPA, UMTS, and Wi-Fi systems.
  • DAS and independent Femto/Wi-Fi system simulation.
  • SINR and best server prediction.
  • Co-channel interference reduction in HetNets through eICIC, dynamic power and channel allocation.
  • Semi-dynamic simulation: for each Monte Carlo snapshot of user locations, multiple TTIs are simulated to ensure RRM and mobility management algorithms are correctly represented.
  • Voice, video, web browsing, FTP, full buffer traffic types supported.
  • Uniform and non-uniform or ‘hot spot’ UE density distributions.
  • User-definable traffic maps representing variable service mixes and UE density across coverage area.
  • Monte-Carlo style population of network with UEs for building up statistics.
  • Key performance indicators include: user data rate distribution (e.g. cell edge 5%ile, mean, peak etc.), user QoE, cell load, cell throughput distribution, etc.

Automatic Optimisation

Automatic network optimisation can dramatically reduce the amount of time taken for network planning, optimisation and maintenance. It also helps reduce the skill levels required for network design, optimisation and troubleshooting tasks. iBuildNet includes intelligent optimisation modules which work jointly across indoor/outdoor and different HetNet layers. Modules include Intelligent Cell Optimisation (ICO), Intelligent Frequency Optimisation (IFO), Intelligent Topology Optimisation (ITO), Intelligent Network Profiler (INP) and Intelligent Test Point locator (ITP). These cover the whole lifecycle of small cell/HetNet planning, optimisation and maintenance and help engineers achieve an optimised network topology, assign channels and diagnose faulty elements.

The key features of iBuildNet’s automatic optimisation functions include:

  • ICO: Automatically fine tunes cellsite locations, numbers, transmit powers and antenna types to optimise key performance indicators such as signal strength and leakage.
  • IFO: Optimises the channel allocation and transmitted powers to reduce inter and intra-network  interference and signal leakage.
  • ITO: Optimises both the route of the cables between devices in a DAS and the optimal components between antennas and signal sources. It helps the user obtain the optimal network layout not only in terms of cable route but also the components used.
  • INP: Provides statistics of the network performance in terms of signal strength, not-spots and leakage from indoor to outdoor, facilitating network design and performance analysis.
  • ITP: Identifies an optimal set of test points and locations in a passive DAS system for diagnostic purposes. By comparing the predicted and measured signal strengths at these optimized test point locations, faulty antennas can be quickly and accurately identified.

Report and Quick Notes

iBuildNet automated network planning can help pre-sales engineers to quickly design a network and provide quotes immediately.The key features of iBuildNet’s quick quotes facility include:

  • Provides customisable report generation to meet the need of various users.
  • Generates a range of report types: Antenna EIRP, cable routing, equipment budget, equipment list, layout plan, and project budget.
  • Auto generation of devices needed, cost of devices, installation cost and other costs.
  • Auto generation of network plan with QoE and associated BoM.
  • Tablet version provides rapid on-site network design.

Quick quotes, accurate prediction of network KPIs and eye catching visualisation will help network equipment vendors win bids from operators. They also help operators estimate the cost of a network with the required QoE.

Summary

The rise of mobile data is changing the shape of mobile networks. The need for more capacity is driving densification while the move to indoor consumption requires in-building systems including DAS, Wi-Fi and small cells technologies. All of these interfere with each other and the existing macrocell network coverage and so need to be co-ordinated using HetNet technologies such as eICIC. RF planning tools will continue to play an essential role in the design of cellular networks, but will increasingly need to offer greatly enhanced functionality and flexibility if they’re to meet the emergent needs of the HetNet era.

They will need to:

  • Simultaneously model both indoor and outdoor environments and their radio access networks.
  • Represent HetNet interference co-ordination technologies such as eICIC.
  • Automate network design and configuration to enable quick estimates of infrastructure upgrade costs.
  • Model small cell backhaul and take its cost into consideration in automatic site selection.
  • Ease the integration of these activities into existing processes and workflows by working with standard data formats, having customisable APIs, and offering a range of output formats that can be tailored to the user group.
  • Be suitable for a range of user groups throughout the design, deploy and maintain upgrade lifecycle of the network.

iBuildNet by Ranplan is an all-in-one solution for HetNet design and performance analysis. It is being continually improved to better serve needs of equipment designers, network operators, services and assurance groups. Please contact us if you would like to find out more or see a demonstration.

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