Carrier Wi-Fi: What is it?

Carrier Wi-FiWith more mobile network operators using Wi-Fi to complement their radio access networks, one begs the question: how’s “carrier Wi-Fi” different from the one I have at home? What exactly is “carrier Wi-Fi”?

While there is no proper, or exact, definition for carrier Wi-Fi, I think it’s more important to realize that the definition has been evolving with time. Personally, I think carrier Wi-Fi is focused on two tracks. First, provide the mobile subscriber a better user experience including easy access to the Wi-Fi network and better quality of service; and second, enable the service provider to scale and manage a network of Wi-Fi access points that can reach into the tens even hundreds of thousands of units. From this point of view, carrier Wi-Fi opens a wide door for differentiation in both equipment ecosystem and service offering. Continue reading →

On LTE-Advanced and Carrier Aggregation

LTE-AdvancedNews of LTE-Advanced is making headlines. SK Telecom aggregated two 10 MHz carriers in 800 and 1800 MHz to achieve 150 Mbps downlink throughput with a version of the Samsung Galaxy S4 handset built upon Qualcomm’s Snapdragon 800 SoC. Verizon announced that its LTE network is nearly complete and suggested carrier aggregation (CA) is the next step. AT&T on the other hand has plans to use carrier aggregation over its 700 MHz unpaired lower D and E blocks. Continue reading →

New Frontiers in Personal Communications (and Investment Opportunities!)

60 GHz 802.11ad Wi-FiIn the late 1880’s, Heinrich Hertz’s experiments with wireless signals were in the VHF/UHF bands (60 to 500 MHz). The first transatlantic transmission in 1901 by Marconi was either around 850 kHz or in the neighborhood of 100 kHz: he simply did not have reliable equipment to measure the frequency. With these modest starts, advances in communication system technology kept opening new spectrum frontiers. Today, we are pushing the limits of commercial communications into the 100 GHz range, a million time higher frequency than what Hertz and Marconi experimented with. There is no talk of “spectrum crunch” in the millimeter wave bands (30 – 300 GHz). Specifically, the 60 GHz ‘V-band,’ which is designated for unlicensed use, is set to experience strong growth as IEEE 802.11ad-compliant silicon is commercialized. Continue reading →

Small Cell World Summit 2013: Wireless Analytics to the Forefront

Wireless AnalyticsThe Small Cell World Summit just concluded, so I would like to summarize my thoughts and impressions from this event. For a little perspective, the conference is sponsored by the Small Cell Forum, which was called the Femto Forum before it rebranded in February 2012. In alignment with this new vision, the 2013 edition of this conference featured for the first time a stream focused on backhaul for small cells. In addition, the scope was expanded to include many ecosystem players: silicon players, DAS OEMs, satellite communication service and equipment providers, protocol stack vendors, traffic localization and network optimization tool developers, timing and synchronization vendors, and engineering service companies, etc. Operators from all continents were on hand to share their experience. Equipment vendors included also In short, it was a microcosm of Mobile World Congress with a focus on wireless infrastructure, without the large peripheral crowd. Continue reading →

When Will Small Cells Be Deployed? A Case Study of Critical Strategic Planning Options for Mobile Network Operators

When will small cells be deployedThis case study was designed to help answer important questions related to small cell deployments. It is based on a traffic forecast and capacity planning tool developed to aid operator strategic planning activities. The tool can also be used by vendors and other ecosystem players to map their product offering and plan for small cell deployments.

Demand for mobile data services is expanding at a rate ranging between 30-60% per year. Subscribers have a choice between many different plans and mobile devices. Networks feature multiple technologies (e.g. 2G/GSM, 3G/HSPA, 4G/LTE) operating in different frequency bands. All this has combined to increase the complexity of technology planning.  Outdoor compact base stations operating at low elevation above ground using licensed frequency spectrum form small cells that work to fill the projected gap between the supply and demand of mobile data capacity. This case study serves to illustrate some strategic options to consider when making small cell buildout decisions. It builds on numerical models to answer a fundamental question: when are outdoor small cells needed? It also illustrates the factors that impact the number of required small cells, the effects of Wi-Fi offload and other strategic technology options such as spectrum. Continue reading →

Australian Digital Dividend Spectrum Auction Concludes by Raising $2 Billion.

Australia Spectrum AuctionThe Australian Communications and Media Authority (ACMA) announced last Tuesday the results of the 700 MHz & 2500 MHz spectrum auction. A total of AU$ 1.96 billion (US$ 2.02 billion) was raised by licensing a combined 200 MHz in these two bands. Telstra & Optus won 2×20 and 2×10 MHz, respectively, in the 700 MHz Band. Yet, 30 MHz in this band remains unsold. In the 2500 MHz band, Telstra and Optus secured 2×40 MHz and 2×20 MHz, respectively. TGP Internet secured a 2×10 MHz license. The duration of licenses in both bands is 15 years. The table below shows the total amounts paid by each operator. Continue reading →

The Shifting Paradigm of Mobile Network Operations

paradigm shiftThe deluge of demand for mobile data has been much discussed and talked about. News is abounding with figures, quotes and graphics of the increasing consumption (about doubling every year) and its projection to the future (anywhere from 10-25 time increase within the next 4 years). On the other hand, there has not been much discussion on what this mean from an operational perspective for the network operator. So, what is going on and what do we see? Continue reading →

Cloud RAN vs. Picocells: The Need for Integrative Approach in Next Generation Network Design.

Picocell vs. Cloud RANWhen it comes to deciding on deploying small cell base stations, one is faced with a few options. One option is based on cloud RAN architecture with remote radio heads connected through optical fiber to a central base station housing the baseband processing. A second option is that of a compact base station which includes both the radio frequency and baseband processing functions. The compact base station is connected to the core network by a number of different backhaul technologies.

The availability of low cost fiber is a gating factor in deploying cloud RAN architecture. Remote radio heads require very high capacity links to support modern air interface features such as multiple antennas for MIMO. CPRI and OBSAI interfaces run at between 3 and 6 Gbps depending on the number of supported antennas. The compact base station on the other hand requires much lower capacity for backhaul – on the order of tens to over a hundred Mbps.  Low backhaul throughput requirements should translate into lower deployment cost to the advantage of compact base stations. Continue reading →

Should Small Cells Be Deployed In Their Own Spectrum Band?

Small cells raise a number of practical implementation questions which are yet to be resolved. One such question is whether small cells should operate in the same frequency band as the macrocell layer (co-channel deployment), or on a different frequency band. The question has profound implications to operators, vendors, and to regulators alike.

To clarify, recall that in co-channel small cell operation interference between the macrocell and small cell layers limit the capacity gain of small cells. The benefit from small cells is realized when they are placed in traffic hot spots whose location must be identified (which is a challenge in itself). As LTE technology matures with advanced releases, techniques such as ‘Almost Blank Frame‘ are introduced to manage interference whereby a layer temporarily ceases operation to reduce interference to the second layer as shown in Figure 1. These techniques largely trade off some capacity for lower interference (but not network capacity: network capacity would still increase because small cells are added).  Using a different frequency band for small cells provides yet higher capacity because the different layers are separate networks. Continue reading →

Mobile Data Traffic Predictions Say: It’s WiFi Offload!

Mobile Data - Small Cell NetworksIf you’re in the wireless infrastructure business, you’ve seen it many, many times. I’m talking about the predictions showing exponential mobile data traffic growth. Hardly a conference presentation goes by without seeing this graph on the first or second slide. It became customary to preface any discussion with this context, often with the idea to get people salivating at a potential windfall of profits from selling systems, software, or services. But predictions are tricky, and mobile data predictions are particularly tricky. A sober read of the facts and what’s behind the headlines is revealing.

Let’s have a look at Cisco’s latest VNI was released earlier last month. It includes a significant reduction in estimated mobile data traffic of about a third for 2012-2016 from those estimated a year ago (29% reduction for 2012). Cumulative average growth rate drops from 78% (18x) to 66% (13x) for the 5-year period ending 2016 and 2017, respectively. Mobile data growth, although still substantial, is not as high as we thought it is, and it is continuously being downgraded every passing year. Predicting data growth is tough business. Continue reading →

Unleashing the Power of HetNets: Interference Management Techniques for LTE-Advanced Networks

In my earlier blog post, The Hype & Reality of Small Cells Performance, I provided a qualitative review of small cell performance and discussed interference scenarios that limit performance. Perhaps the most defining problem of small cell deployments is the large transmit power imbalance between the macrocell and the small cell (~20-30 dB) which increases the potential of uplink and downlink interference thereby limiting the ‘cell-splitting gain.’ As interference is the culprit in limiting performance, so managing it is at the crux of advanced LTE techniques. Fortunately, the LTE physical layer provides many levers to manage interference. Let’s recall that LTE is based on orthogonal division multiple access technology (OFDM) where orthogonal sub-carriers divide a wide channel bandwidth into multiple narrow frequency bands. Data is scheduled on sub-carriers which are assigned to users in the frequency and time domains (the basic unit of assigned sub-carriers is called a Resource Block). As we shall see, many of the interference management techniques are related to how the network assigns and manages its resources. But before we get into this, let’s have a look at range expansion which is a fundamental aspect of small cell deployments. Continue reading →

Word Clouding MWC: Observations and Takeaways.

MWC Cloud LogoMWC is over. In reflecting on the show, I came up with an idea and tried it out, just for fun. What if I take all the news coverage from the show and generate a ‘word cloud,’ would I be able to zoom in on the few key trends? What would ‘word clouding’ tell me? As it turned out, it was much more work than I had anticipated, but it was an interesting process. I’ll take you through this while I add my observations on the show. Continue reading →

UK 4G Spectrum Auction Concludes – A Brief Analysis

4G Spectrum AuctionThe long-awaited 800 MHz and 2600 MHz UK auction concluded today with a total of £2.34 billion, or $3.63 billion (Ofcom set reserve price at £1.3 billion). The winners of 60 MHz of digital dividend spectrum in 800 MHz band include EE, 3G, O2 and Vodafone. In the 2.6 GHz band, Vodafone, EE and BT divided 185 MHz among them with the lion share going to EE who got 75 MHz of paired spectrum. The winners will participate in a second round to decide on the exact frequency allocations. Continue reading →

The Hype and Reality of Small Cells Performance

Heterogeneous networks (HetNets) consist of large (macro) cells with high transmit power (typically 5 W – 40 W) and small cells with low transmit power (typically 100 mW – 2 W). The small cells are distributed beneath the large cells and can run on the same frequency as the large cell (co-channel), or on a different frequency. As an evolution of the cellular architecture, HetNets and small cells have gained much attention as a technique to increase mobile network capacity and are today one of the hot topics in the wireless industry. Many of the initial deployments of small cells are of the co-channel type. Standards such as LTE have focused on incorporating techniques to improve the performance of co-channel deployments in earlier releases of the technology standard leaving the handling of multi-frequency deployment type to later releases. In all, operators today have multiple options of small cell deployment scenarios, operational techniques and technology roadmaps to choose from. Continue reading →

More and More Small Cells, But Where’s the Gain?

Small Cell StrategySmall cells are meant as a solution to address the explosive growth in mobile data services, right? Well, the answer is: it depends! They can be a solution under certain conditions, but not always. Yes, there could be situations where small cells add little if any gain. In fact, more than one operator mentioned to me little or even no gain in overall capacity increase by their small cell pilot projects. So what’s happening, and why can we run into situations where small cells don’t deliver on their promise? Continue reading →