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Rising to Meet the 1000x Mobile Data Challenge
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Rising to Meet the 1000x Mobile Data Challenge Table of Contents 1 Executive Summary
2 More Spectrum – Licensed, Unlicensed, and an Innovative Approach
2.1 Authorized Shared Access (ASA)
3 More Small Cells – Taking Hetnets to a New Level
3.1 Wireless Backhaul and Relays
4 More Indoor Deployments – Evolve from Outside to Inside............ 9 5 Higher Efficiency – Across Networks, Devices and Applications/Services
Copyright © 2012 Qualcomm Incorporated. All Rights Reserved page 1 Rising to Meet the 1000x Mobile Data Challenge 1 Executive Summary The mobile industry has a history of overcoming great obstacles, and today we’re facing a formidable one: the “1000x challenge.” The genesis of this term is rooted in the phenomenal growth in the global demand for mobile broadband data services—mobile data traffic has been approximately doubling every year. All the indications point to this growth continuing unabated. While the projections vary, the goal of “1000x increase” truly captures the sentiment of the industry.
The positive news is that mobile industry’s latest wireless technologies offer solutions capable of meeting the 1000x challenge—some of which are already developed—and there is a robust roadmap for many more. The solutions are not simply about throwing more resources at the challenge. The solutions require a radically different approach to acquiring, deploying and managing resources.
The focus of this paper is to set a vision for the efforts needed by the industry to meet the 1000x challenge as well as provide solid proof points for the initial concepts and technologies that are building blocks of the overall vision.
Conceptually, all the efforts can be summed up in to three main groups: 1) more spectrum; 2) small cells everywhere; 3) higher efficiency across the system.
Spectrum is the life blood of wireless networks. There are many enhancements to increase the efficiency of existing spectrum. But meeting an increase of the magnitude
of 1000x will unquestionably require more spectrum. The questions to ponder are:
how much more, which bands, licensed or unlicensed, and how to get it in a timely manner?
Small cells are already popular and are here to stay. How dense can they get, and where—indoor, outdoor or both? All indicators say that most mobile traffic will occur indoors. Small cells are a good match there. Does this mean a small cell in every house, shop or office? What about the interference? How about new deployment models? Finally, how do you get higher efficiency from all the networks, devices, applications and services? Does the notion of “the whole is much more than the sum of its parts” hold true in this case?
This paper explores all these questions, sometimes proposing unconventional solutions and path-breaking approaches. Our end goal is to show that the mobile wireless industry can cost-effectively face the 1000x challenge while continuing to provide the best possible mobile broadband experience to users.
Copyright © 2012 Qualcomm Incorporated. All Rights Reserved page 2 Rising to Meet the 1000x Mobile Data Challenge 2 More Spectrum – Licensed, Unlicensed, and an Innovative Approach As wireless networks strain to meet the growing demand for mobile broadband services, spectrum has become a hot-button issue. Operators are always looking for more of it at bands that are suitable for their use in a cost-effective way. At the same time, regulators are working to identify, clear and allocate new spectrum for mobile services. As shown in Fig. 2.1, there are three approaches to making new spectrum
1) Traditional licensing process for 3G and 4G
2) A new and innovative regime called Authorized Shared Access (ASA)
3) Unlicensed approach for Wi-Fi services Fig. 2.1 Sources of new mobile broadband spectrum Each of these approaches has a specific usage scenario. The traditionally licensed spectrum gives exclusive rights to the licensee on a nationwide, 24x7 basis. The exclusive use allows planned and orderly deployment, resulting in predictable performance. Identifying, allocating and clearing this spectrum is a long and arduous process. Globally, regulators have demonstrated the effectiveness of this approach.
In cases when the spectrum cannot be cleared for licensing within a reasonable timeframe, or on a nationwide basis, Qualcomm and its partners are proposing a new approach called ASA. ASA can potentially unlock a large quantity of underutilized high-quality spectrum in higher bands for 3G/4G services, in a cost-effective and
timely manner. ASA also allows predictable Quality of Service (QoS), which is important for consumers. Section 2.1 discusses ASA in detail.
Globally, Wi-Fi uses unlicensed spectrum in the 2.4 GHz and 5 GHz bands. In this spectrum, by definition, no single entity has control over how the networks are planned, deployed and used. Because of this, the interference situation for very dense deployments is unpredictable, making it difficult to guarantee QoS for delay-sensitive apps such as multiplayer interactive games, VoIP, video telephony, etc. For other applications, Wi-Fi works fine, and hence the popularity of Wi-Fi is skyrocketing, prompting the need for additional spectrum allocation. There is an effort in the U.S. to allocate an additional 195 MHz of spectrum in the 5 GHz band. Also, the 60 GHz band is already earmarked for specific Wi-Fi applications such as wireless displays and wireless docking operating within a very close range (e.g., within a room).
Wireless evolution enhancements such as spectrum aggregation and supplemental downlink can further increase the usability of the entire available spectrum. Spectrum aggregation can be done between different bands of the same technology (e.g., 900 MHz and 2.1 GHz of HSPA+), which is possible today, or across different technologies (e.g., LTE with Wi-Fi) in the future. Supplemental downlink, on the other hand, combines unpaired spectrum with the downlink of paired spectrum, considerably augmenting downlink capacity.
As the industry is working tirelessly to identify new globally harmonized bands for mobile services, it is evident that exploring higher bands is one of the options. The 3.4–3.8 GHz spectrum is one such band. Because of its propagation characteristics that lead to smaller coverage area, this band is suitable for small cell deployments.
Parts of this spectrum may be available to be licensed traditionally, and others can be licensed through ASA.
2.1 Authorized Shared Access (ASA) Spectrum being a finite resource, every effort should be made to utilize it to the fullest extent possible. But some spectrum holders, such as government users, because of the nature of their operations, may not be using the entire block of allocated spectrum in every part of their geographic boundaries on a 24x7 basis. For example, while spectrum for military radar might be allocated on a countrywide basis, the radar operations may only be using the spectrum at certain locations such as along the coastline, or may not be using it 24x7. There are many similar examples in a variety of sectors including defense, satellite communications, and many more.
ASA proposes a new regulatory framework for such instances. It allows the grant of exclusive spectrum rights of use to qualified stakeholders, to operate a commercial 3G/4G network in this underutilized spectrum, whenever and wherever it’s available,
subject to the usage needs and requirement of the incumbent spectrum rights holder.
Here’s one example of how this could work. In a simple process, the incumbent spectrum rights holder, the 3G/4G operator and the regulator sign a compensationbearing agreement that makes the incumbent’s spectrum assets available for mobile broadband usage by the 3G/4G operator after they obtain a license. Or, the exclusive ASA rights could also be auctioned subject to the defined usage needs of the incumbent. No matter what the arrangement is, there will only be one stakeholder using the spectrum at any given time within the defined geographical boundary. This shared exclusive use ensures predictability in terms of availability and performance (because of guaranteed non-interference) for 3G/4G operators. Furthermore, this predictability offers protection for operator investments.
From an incumbent’s perspective, ASA offers an opportunity to monetize its underutilized spectrum assets without hampering operations in any way, as the agreement ensures that there will absolutely be no undue interference from the 3G/4G operations while using the ASA spectrum. From the operator’s perspective, ASA allows it to access high-quality 3G/4G spectrum whenever and wherever needed.
From the government’s perspective, ASA helps ensure that spectrum is used efficiently and the derived benefits will spread across the economy.
Since it is critical for 3G/4G operators not to interfere, small cells using higher frequency bands are the ideal option for ASA, thanks to their lower transmit power (coverage) and their indoor or low-height outdoor deployments. This is important as it allows small cell deployments geographically closer to incumbents’ operations.
Macrocell deployments are also possible farther away, as shown in Fig 2.2.
ASA can potentially unlock hundreds of megahertz of high-quality spectrum for 3G and 4G. Qualcomm along with its partners is already working on identifying globally harmonized spectrum bands for ASA. The initial focus is to target bands for which commercial devices are either already available in the market or will soon be available. For example, the 2.3 GHz band is a prime ASA candidate for Europe as this band is earmarked for LTE in China and India, and for which commercial devices are available. The 3.5 GHz band is also another attractive ASA candidate for the U.S., Europe, Latin America, Southeast Asia and Middle East. The advantage of using harmonized bands with commercial devices is that operators can quickly start using the ASA spectrum and leverage large economies of scale. Moreover, ASA doesn’t need any standards change, making it simple to deploy.
In essence, everyone wins with ASA—it offers compensation for incumbents; it provides cost-effective, high-quality spectrum for 3G/4G operators; and it offers a pragmatic, fast-track solution for regulators to increase the efficient use of spectrum and to address the ever-increasing demand for new mobile broadband spectrum.
3 More Small Cells – Taking Hetnets to a New Level The benefit of small cells in providing capacity where needed, is well understood. So are the challenges and solutions for managing the interference. Enhancements such as “Range Expansion,” introduced in LTE Advanced, increase the overall network capacity much more than what can be got by merely adding small cells. The interference management techniques of LTE Advanced make adding more small cells possible without affecting the overall network performance.
To reach the 1000x capacity goal, we will need many more small cells. We will need them everywhere (indoors and outdoors), at all possible venues (residences and enterprises), and capable of managing all technologies (3G, 4G, Wi-Fi). Furthermore, the “small cells” will be all types, including femtos, picos, metros, relays, remote radio heads, distributed antenna systems, etc. As shown in Fig. 3.1, all of these small cells will complement the traditional macro networks, and allow denser use of spectrum, making the network completely heterogeneous, often referred to as hetnets.
Fig. 3.1 – Small cells allow denser use of spectrum Extremely low-cost indoor small cell solutions can be used at homes, offices, enterprises, shopping malls, etc., and for the most part, can be installed by users themselves. Small cells can also be deployed by operators as hotspots, costeffectively serving highly concentrated indoor/outdoor traffic. Relays are an ideal solution for backhaul-challenged areas, as they use part of their capacity for backhaul.
No matter what kinds of 3G/4G small cells are deployed, integrating Wi-Fi into all of them makes perfect sense. Wi-Fi can opportunistically offload a substantial amount of data traffic from 3G/4G, whether it’s an indoor or outdoor deployment, or a hotspot.
Our initial studies have shown that the overall capacity of these hetnets scales with the degree of densification of small cells, thanks to advanced interference management techniques. Fig. 3.2 clearly illustrates this by showing the relative capacity increase with the increasing penetration of small cells in a LTE Advanced network. For example, if there are 32 outdoor picocells for every macrocell in the network, then the overall capacity will be a staggering 37x (approx.) capacity gain over a macro-only network.
Copyright © 2012 Qualcomm Incorporated. All Rights Reserved page 7 Rising to Meet the 1000x Mobile Data Challenge Assumptions: Pico small cell, 10 MHz@2 GHz + 10MHz@3.6 GHz,D1 scenario macro 500m ISD, uniform user distribution scenario. Gain is median throughput improvement, from baseline with macro only on 10 MHz@2 GH, part of gain is addition of 10 MHz spectrum. Users uniformly distributed—a hotspot scenario could provide higher gains. Macro and outdoor small cells sharing spectrum (co-channel).
lesser issue, as users are expected to bring their own backhaul, be it DSL, cable or fiber. A large portion of the outdoor deployments could also be backhauled by fixed network.