One consideration on the design of any wireless system is future support for next generation technologies. Some consideration should also be given to the inevitable convergence of cellular and Wi-Fi which is increasingly integrated with enterprise wireless systems.

In-Building Enterprise Wireless

Enterprise wireless is already a growing sector as mobile devices drive connectivity away from fixed desktop PCs to meet the needs of a mobile workforce. Cloud computing further serves to increase the need for better communications as applications and servers become decentralized requiring enterprises to invest in high capacity connectivity between office and campus and external cloud based service providers. The move to Cloud based mobile Apps makes support for high quality in-building enterprise wireless a growing requirement.

Wi-Fi, originally a convenience is now mission critical for most business yet its design is still largely ad hoc and deployed reactively. Capacity is fast becoming the driving factor for Wi-Fi and a professional design is critical given the very limited spectrum available and many sources of interference. However, Wi-Fi is only available on a localized basis as the “last few feet” of an existing enterprise network and not suitable for wide area or even broad campus connectivity. Cellular is thus an important and complementary part of any enterprise deployment.

By comparison, the original use case for cellular (which has dictated its design since its inception), was support for voice and later data communications when out of the office. In each case un-tethered operation when primary communications were unavailable. As the world inexorably adopts mobile platforms as a primary rather than a secondary means of interaction, the importance of ubiquitous mobile support becomes critical. This implies that cellular, rather than being a distinct network with its own subscribers, is only one of several methods for a business to connect with its customers, prospects, vendors and employees.

Cellular and Wi-Fi are increasingly seen as extensions of business networks, different routes to connect, each suitable for certain environments and each equally important. There is a clear and growing convergence between these technologies and buildings owners should consider the long term impact and requirements which will allow continued integration and expansion.

Additionally, the technologies which are at the heart of both cellular and Wi-Fi are increasingly similar. The chips perform similar tasks using similar advanced mathematical approaches to eke the last few bits per second out of each hertz of spectrum albeit with different coverage and capacity goals. Further convergence is inevitable and thus emerges the concept of an integrated network design which embraces both local Wi-Fi as an extension or primary component of an enterprise network, and cellular as the wide area macro connectivity component. Equipment OEMs are already contemplating these converged networks with small cells and DAS at their core, coupled with high capacity infrastructure to link them to existing corporate resources.

They key thought here is that delivering Wireless Capacity is a constrained problem, limited by spectrum and interference and as such must be planned and designed with far more consideration than a wired network. In the future , the Wi-Fi component must be designed with similar precision as cellular networks are for the same reasons of interference mitigation, spectral efficiency and system capacity. Additionally , if cellular head ends are deployed at the same locations (or if integration at the component level makes it cost effective to deploy dual mode equipment), then network planning, design and ongoing performance validation will become vital to ensure optimal performance, future scalability and cost effectiveness.

It is equally possible that the deployment of wireless support will drive the interconnectivity and backhaul functions (current riser and structured cable networks) rather the other way round, where today these interconnects typically dictate where wireless can be deployed. A truly ‘connected’ business campus of the future may consider Mobile First and construct supporting infrastructure at the design stage with the primary goal of expandable mobile connectivity in mind.

Wi-Fi Calling as a Factor

Wi-Fi calling is a supporting actor in the above thesis. Cellular Operators are keen to offload traffic to enterprise class Wi-Fi as the cost per bit delivered of a Macro network does not support the high equipment cost to add capacity externally. This in turn implies that the Wi-Fi system they hand their traffic off to must be equal in quality to that of the offloading cellular network.

Operators have realized that further extending voice networks into buildings is prohibitively costly but offloading to Wi-Fi may allow them to support calls in most in-building environments thus retaining customers and justifying their Average Revenue Per User, (ARPU). There is a growing need to simplify the hand off process and improve the quality. Schemes such as Passpoint assist this goal. Promoted by the Wi-Fi alliance with support from the Cellular Operators, Passpoint aims to make Wi-Fi a “true extension of service provider networks,” letting users roam from one hotspot to another with no manual effort, just as cell phone owners already switch seamlessly from one cell tower to another.

With Passpoint, devices automatically identify and join Wi-Fi networks, and users are not required to complete a cumbersome manual login process. Passpoint also automatically configures industry-standard WPA2 security protections without user intervention.

A corollary is that the traffic that once was on the periphery of cellular systems will be handed off to in-building resources further increasing capacity and quality requirements on the In-Building DAS and Wi-Fi system. This underscores the need to provide wireless as a primary not a secondary service and requires careful planning and integration.

LTE-U and LAA

A new consideration may include an even tighter integration between licensed and unlicensed spectrum. Carriers paid $48B for small slivers of spectrum in the high frequency AWS band and the recent 600MHz band auction raised nearly an additional $20B. T-Mobile US, Dish Network and Comcast walked away as the highest bidders in the FCC’s 600 MHz incentive auction process, with the three accounting for $15.9 billion of the auction’s $19.8 billion in net proceeds.

Spectrum is a limited resource and very valuable and operators view the existing unlicensed bands as a possible source of free spectral resources.

Licensed Assisted Access (LAA) was introduced in 3GPP release 13 as part of LTE Advanced Pro and is one of several schemes proposed to allow LTE to operate and co-exist in unlicensed bands (Wi-Fi spectrum) without impacting the performance of Wi-Fi. It uses carrier aggregation in the downlink to combine LTE in unlicensed spectrum (5 GHz Wi-Fi Spectrum) with LTE in the licensed band. This aggregation of spectrum provides for a fatter pipe with faster data rates and more responsive user experience. For example, a mobile operator using LAA can support Gigabit Class LTE with as little as 20 MHz of licensed spectrum. By maintaining a persistent anchor in the license spectrum that carries all of the control and signaling information, the user experience is expected to be both seamless and reliable.

Another possibility is the very unique CBRS (Citizens Broadband Radio System) which uses the 3.5GHz (3550MHz to 3700MHz) spectrum to provide LTE based wireless voice and data service. Unlike previous spectrum allocations this is based on an innovative and somewhat experimental spectrum sharing framework intended to improve utilization and spectrum efficiency.

When deployed it will bring integrated LTE based services to buildings at the cost of increasing complexity and the likely requirement that wireless systems be designed as integrated systems with as much care taken as is currently expended on designing Macro cellular and small cell systems. It will also inevitably affect the spectrum that is available for Wi-Fi and impact the selection of location points for integrated systems. It also indicates the future benefits of scalable converged DAS systems where a building owner can control their own network and resource allocations.

MobileNet Services, Inc.

MobileNet provides a full range of turnkey engineering and consulting services for every stage of network deployment, integration, optimization, performance validation and compliance testing to major telecom operators and OEMs across the nation. We have led deployment of 2G, 3G, and 4G networks for over a decade and have launched over 25,000 UMTS sites and over 5,500 LTE turnkey sites across the U.S, with deep domain expertise that spans GSM through CDMA, to LTE, WiFi, VoLTE, and beyond. We also provide validation services, where our significant experience in all major wireless protocols makes us the ideal partner system testing and validation of advanced wireless services and devices.

We are a leader in DAS System Verification, Optimization and Design with extensive experience testing over 2500 high profile venues including airports, stadiums, hotels, amusement parks, universities, and business parks. Our long lasting customer relationships attest to our reputation for Quality, Expertise, and Reliability and reflect the integrity we bring to delivering superior services, on time and on budget.