The Opportunities and Challenges of LTE Unlicensed in 5 GHz
David Witkowski, Executive Director, Wireless Communications Initiative
In 1998, the Federal Communications Commission established the Unlicensed National Information Infrastructure or U-NII 5 GHz bands. These are used primarily for Wi-Fi networks in homes, offices, hotels, airports, and other public spaces and also consumer devices. U-NII is also used by wireless Internet Service Providers, linking public safety radio sites, and for monitoring and critical infrastructure such as gas/oil pipelines.

MMD March 2014

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Band Reject Filter Series
Higher frequency band reject (notch) filters are designed to operate over the frequency range of .01 to 28 GHz. These filters are characterized by having the reverse properties of band pass filters and are offered in multiple topologies. Available in compact sizes.
RLC Electronics

SP6T RF Switch
JSW6-33DR+ is a medium power reflective SP6T RF switch, with reflective short on output ports in the off condition. Made using Silicon-on-Insulator process, it has very high IP3, a built-in CMOS driver and negative voltage generator.

Group Delay Equalized Bandpass Filter
Part number 2903 is a group delayed equalized elliptic type bandpass filter that has a typical 1 dB bandwidth of 94 MHz and a typical 60 dB bandwidth of 171 MHz. Insertion loss is <2 dB and group delay variation from 110 to 170 MHz is <3nsec.
KR Electronics

Absorptive Low Pass Filter
Model AF9350 is a UHF, low pass filter that covers the 10 to 500 MHz band and has an average power rating of 400W CW. It incurs a rejection of 45 dB minimum at the 750 to 3000 MHz band, and power rating of 25W CW from 501 to 5000 MHz.

LTE Band 14 Ceramic Duplexer
This high performance LTE ceramic duplexer was designed and built for use in public safety communication and commercial cellular applications. It operates in Band 14 and offers low insertion loss and high isolation to enable clear communications in the LTE network.
Networks International

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January 2013

Is Your Smart Device’s Internet Running Slow? Maybe it’s Time to Question Your Service Provider’s Wi-Fi Testing Solution
By Olga Yashkova-Shapiro, Program Manager, Measurement & Instrumentation Practice, Frost & Sullivan

As there is an increase in the number of mobile subscribers and users of smart devices, there is a growing demand for non-voice traffic, such as data and video streaming. This, in turn, presents a challenge for the communication industry, which has limited and licensed bandwidth issues.

Above all else, Wi-Fi technology has come out as the most popular solution for wireless Internet traffic because it is economical, unlicensed, all-encompassing and widely adopted. Additionally, it has transformed from being a convenience service offered in coffee shops and hotels into a rugged, scalable and resilient carrier-grade network service.

The Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a set of standards for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6, and 5 GHz frequency bands. Wi-Fi technology has seen a steady introduction of standards since 1997, starting with 802.11a, followed by 802.11b/g/n. This transition has seen an increase of maximum throughput from 2 Mbps for the 802.11 to over 600 Mbps for the 802.11n standard because of wider bandwidth, multiple spatial streams, higher modulation, and new antenna technologies, such as multiple input multiple output (MIMO).

The introduction of the latest 802.11ac standard will replace all existing products with the 802.11n standard in the next five years. This technology, also known as 5G Wi-Fi, 802.11ac, operating in the less crowded 5 GHz bandwidth, incorporates the latest technologies from the Wi-Fi Alliance to provide higher throughput in the range of 3 to 4 Gbps.

From a test and measurement perspective, the emergence of these highly technical and complex technologies creates a large number of opportunities for equipment vendors. The focus of a recently published Frost & Sullivan study is to discuss and analyze the various types of test equipment and technologies that are likely to advance the growth of the Wi-Fi test equipment market.

Cellular Offload
More recently, service providers (SPs) have identified Wi-Fi as a solution to cellular offload. Offloading traffic in high-demand areas from the cellular network to Wi-Fi hotspots increases the performance and capacity of the network, with the added advantage of reduced cost to provide data for mobile operators.

To ensure seamless operation and improved security between Wi-Fi and cellular networks, standard bodies such as the Wi-Fi Alliance and 3GPP are introducing new standards such as the next-generation hotspot (NGH 2.0) and 3GPP I-WLAN (Release 10) standards, which will also provide a standard testing protocol for test equipment vendors.

Cellular service providers (SPs) are currently working on their Wi-Fi offload strategy to provide carrier-grade Wi-Fi, which is absolutely critical. Wi-Fi has been around for a long time, however the quality of service it offers has been very inconsistent. Historically, Wi-Fi has been offered for convenience by hotels, coffee shops, and certain other places. However, the situation is changing, as operators need to offload the traffic as much as possible to clear up the capacity of their cellular networks. In addition, they want the offload procedure to be as seamless as possible. The goal of SPs is to achieve the seamless offload transition without users having to manually connect their device to the nearest Wi-Fi network. Thus, when a smart device enters into the range of a Wi-Fi network, it should automatically transition to the appropriate authorized network, possibly without the user even knowing what network they are using to transmit data at any given moment.

However, through the above-mentioned scenario, if the Wi-Fi experience is not acceptable, the user does not blame the hotel or a coffee shop for the poor Wi-Fi network, rather their current service provider. The implications on customer churn are tremendous if operators do not conduct the offload procedure right. As such, Wi-Fi should be carrier-grade and expand beyond small businesses deploying it. Currently, SPs and vendors are still looking at signal strengths that, unfortunately, do not show how many users are already on the network, how congested it is, as well as whether it is configured correctly beyond the access points. A solution had emerged from players such as Ixia that presents traffic over the air and measures the performance that the user actually receives from the Wi-Fi networks.

Demand for Wi-Fi Test Solutions is on the Rise
The global Wi-Fi test equipment market generated revenue of $159.4 million in 2011. In 2018, revenue is expected to reach $442.6 million at a CAGR of 15.7 percent.

Figure 1 represents the revenue forecasts for the Global Wi-Fi test equipment market for 2011 and 2018.

Figure 1: Wi-Fi Test Equipment Market: Revenue Forecasts (World), 2011 and 2018

According to ICT Statistics, the number of cellular connections is presently estimated at 6.6 billion units and is expected to grow to 10 billion units by 2016. Furthermore, there has been an increasing demand for non-voice traffic (data/video streaming) on cellular networks. These cellular networks will face a tremendous challenge to cope with a limited and licensed spectrum. Wi-Fi, which utilizes the unlicensed spectrum, is the most favorable technology for offloading this demand because it is inexpensive, pervasive, gives high performance, and has constantly improving standards.

Targeting high-demand areas and offloading data from cellular to Wi-Fi hotspots will improve the customer experience by increasing the mobile network’s capacity and performance, while simultaneously lowering the cost to deliver data for the service provider.

The risk to service providers of using Wi-Fi for cellular offload is that unsatisfactory user experiences with Wi-Fi will result in a loss of high-margin smartphone customers. Service providers will make every reasonable effort to acquire and retain these premium customers in order to sustain and grow their business. The challenge will be to test their offload solutions thoroughly to provide the best service. This trend will encourage new innovations in testing for the Wi-Fi testing industry.

Figure 2 illustrates the drivers of Wi-Fi test equipment market.

Constantly Improving Standards
The introduction of 802.11n brought along with it several new technologies such as MIMO, 3X3, and 4X4 in the Wi-Fi standard 802.11, which gave the testing industry a lot of new avenues for testing the new .11n products. Similarly .11ac standard, whose products are expected to launch this year, also introduced a lot of new technologies such as multi-user MIMO, 8X8, and beam forming, which require better and improved test equipment. The .11ad standard, expected to enter the market after 2016, will bring along with it more innovations. As such, the testing industry has the opportunity to constantly innovate and come up with new products to test the improved standard and ensure better-quality products.

Demand for Wi-Fi-Enabled Consumer Devices Shows Steep Rise
So far, only computer electronics equipment and game consoles are Wi-Fi enabled when it comes to home networks. But the quest for connectivity continues to drive consumer electronics (CE) manufacturers to enable their products with Wi-Fi technology.

The .11n is on the fringe of supporting bandwidth required for true high-definition (HD), but it is .11ac that will bring the revolution, as it will have the bandwidth to support multiple devices supporting HD. Across all “digital living room” consumer electronics, which include set top boxes, game consoles, Blu-ray players, digital picture frames, and other devices, Wi-Fi-enabled devices will exceed 200 million units by 2014. This could present significant opportunities for the Wi-Fi testing industry in research and development (R&D) and manufacturing applications.

Multimedia Applications
With the increased adoption of multimedia applications by consumers, the demand for Wi-Fi test equipment is expected to be on the rise as well. According to Craig Mathias, a principal with the mobile and wireless advisory firm Farpoint Group, quick adoption of streaming media, such as voice and video, by consumers creates a significant volume of traffic that can put a tremendous strain on enterprise and especially, home networks. Having functional verification of that kind of capability specifically for capacity will be crucial when testing Wi-Fi.

Enterprise and Business Infrastructure Wi-Fi Adoption
There is an increasing adoption and use of WLAN in companies, small office/home office, hospitals and others. New applications such as health/fitness, medical, smart meters, and home automation are seeing a steady growth and are very important because they have mission-critical devices that need rigorous testing when compared to other device markets, such as consumer electronics.

Low-Cost Wireless Technology
It’s an extremely low-cost technology compared to WiMax/long-term evolution (LTE)/high speed packet access (HSPA), etc. When calculated on the basis of capital expenditure (CAPEX) per Mbps per unit area, the present costs of HSPA and LTE are much more than Wi-Fi. This analysis, though, stands only in dense urban areas. In less dense, rural areas- the cost of deployment is nearly the same and sometimes more. Until the costs of LTE and HSPA come down significantly, Wi-Fi will be the favored choice for wireless Internet access. The huge deployments resulting from this will produce a significant market for testing.

Figure 3 illustrates the challenges of the Wi-Fi test equipment market.

Figure 3: Wi-Fi Test Equipment Market: Key Market Restraints (World), 2011

Challenges for Test Equipment Vendors

Femtocells are seen as potential solutions in the cellular offload market in the longrun, as they offer greater control and enhanced security than Wi-Fi to wireless service providers. However, this is still an emerging technology and it would take time before femtocells could be a threat to Wi-Fi test equipment vendors. In addition, femtocells could be a complimentary offload solution to Wi-Fi, as many base stations include both technologies.

Unpredictable Development of Standards
In the Wi-Fi industry, drafts for new standards come first, then the products, and finally the actual standard from the Wi-Fi Alliance. The final draft released by the Wi-Fi Alliance for any new standard is many times very different from the earlier drafts used to release a lot of products. This causes a lot of ambiguity in the test industry, as there is not a fixed protocol for testing a new standard. As a result, many vendors need to ensure that their products can be updated continuously, otherwise their products could become obsolete within months of their release. As a result, many of them don’t enter the market until the final standard is released. By then, many equipment manufacturers develop ingrown solutions.

Competition from Other Emerging Technologies Such as Zigbee in the Residential Devices Market

Zigbee is used for applications including wireless light switches, electrical meters with in-home displays, and other consumer and industrial equipment that require short-range wireless transfer of data at relatively low rates. This technology can decrease the market for Wi-Fi-enabled devices in household devices (along with Bluetooth™).

Wi-Fi is an Unlicensed Technology
Though the standards are improving, issues remain, such as decreased range for the improved standards, a lot of interference due to overload on the 2.4 GHz, and subsequently on the 5 GHz band. This occurs when Wi-Fi is in the unlicensed band, which is also used by other devices, such as microwave ovens, cordless phones, Bluetooth devices, and wireless video cameras. Testing these products for the above technical constraints will be a challenge.

Wi-Fi Testing Technologies

First-Generation Testing
The first-generation testing tools were primarily focused on the radio frequency (RF) environment, interference, and security using simple testing tools such as:
Laptops/PDAs with sniffers or received signal strength indicator (RSSI) measuring software (site survey tools)

Low-cost spectrum analysis tools: interference detection and characterization
Handheld PDA-type specialty devices, which combined the above two functions
Software packages for propagation simulation and installation management

The above-mentioned approach, however, has a number of problems associated with it. These are listed as follows:

• The best RF signals are not a reliable application performance predictor
• Maximized RF coverage, rather than client count
• Network not optimized for the most important clients (tests conducted were not client specific)
• Results depended on the technician doing the tests

Later testing methods attempted to test the client behavior and measure applications in addition to RF testing. However, the client behavior was isolated from the network behavior; thus, the first-generation Wi-Fi testing methods were not providing a reliable insight into the overall network performance.

Testing Transition from 802.11 a/b/g to n:
The major innovations that were introduced in the 802.11n standard were changes to implementation of Orthogonal Frequency Division Multiplexing (OFDM), introduction of MIMO, MIMO power saving, wider channel bandwidth, and antenna technology, which gave test equipment vendors vast opportunities to expand their product line. At the same time, test vendors were faced with technical challenges to provide test solutions for the above-mentioned technologies.

One of the most difficult challenges was to build a reliable test setup for 802.11n to test MIMO technology. By using more transmitters, MIMO is able to achieve higher throughput. Complex computation and analysis is required to modulate and demodulate the signal. As the MIMO environment is subject to dynamic propagation changes, various fading profiles and test conditions must be applied to test the system performance and robustness. Tests introduced during this period to analyze the performance of access points were: MIMO performance, forwarding rate limits, mode client and protection, QoS, and others, thus increasing the complexity of the test equipment.

Technical Challenges in the Current Standard 802.11ac:
IEEE 802.11ac, positioned as the evolution of 802.11n, claims a sixfold increase in data rate via wider bandwidth, larger quantities of spatial streams, and advanced digital modulation techniques. 802.11 ac is expected to become the mainstream WLAN standard by 2015. In addition, a number of 802.11ac devices will be in production worldwide in 2012.

There are four main technical challenges for 802.11ac manufacturing test equipment:

1) Wide Bandwidth:
802.11ac functions at the 5 GHz license-free bands in the 80 MHz or 160 MHz bandwidth, which is much higher compared to earlier WLAN standards. According to Aeroflex, a single capture of the full signal bandwidth is required for conducting transmitter tests to perform error vector magnitude (EVM), frequency, power, and spectrum flatness measurements. The spectrum mask measurement necessitates the analysis of a significantly wide bandwidth. This operation is executed via spectrum stitching by recording and capturing a number of snapshots of the signal and stitching them in the frequency domain. As far as receiver tests are concerned, it is necessary to generate a full bandwidth signal waveform in order to stimulate the device under test (DUT). This allows receiver sensitivity tests during various modes of operation.

2) Multiple Spatial Streams:
802.11ac standard increases MIMO support up to eight spatial streams, allowing a terminal to transmit and receive a signal to and from several users in the same frequency band at the same time.

In the R&D application, MIMO requires test equipment to perform encoding or decoding of composite signals with multi-path channel emulation. At the manufacturing stage, Wi-Fi test focus shifts to RF component calibration and quality assurance.

3) High-density Modulation:
The 802.11ac release highlights modulation schemes up to 256QAM; that is, four times greater than the 64QAM used in previous WLAN standards. As a result, the required signal quality for higher rate transmission became more challenging. In order to accurately measure 802.11ac signals, it is necessary for the remaining EVM of the test equipment to be better than the lowest EVM requirement (i.e. -32dB at 256QAM) in order not to jeopardize production numbers, according to Aeroflex.

4) Challenges in Wi-Fi Offload Testing:
Apart from the challenges mentioned above, Wi-Fi offload testing is expected to extend from performance tests in the laboratory to over-the-air (OTA) field tests for network assessment, when it is actually set up. Network equipment vendors do most of the testing in the lab using cabled radio frequency (RF) to simulate network loads. With Wi-Fi offload, mobile operators will ensure that site assessment would be an integral aspect of testing, which would require expertise in OTA tests.

Quality of Experience (QoE) is King!
As mobile data continue to increase exponentially with the increasing global adoption of smartphones, the demand to offload data traffic is expected to grow as well. Given the fact that Wi-Fi networks are not carrier-class in quality at this time, it is crucial for SPs and NEMs to test and monitor them to ensure positive QoE for their customers.

The 802.11ac and 802.11ad standards provide enormous opportunities for the Wi-Fi test equipment industry in the next few years. The move to gigabit Wi-Fi is needed to keep up with demand for Wi-Fi network capacity and to enable Wi-Fi to remain key technology at the edge.
The demand for integrated, end-to-end, layer 1 to 7 test solutions continues to increase. With the fixed mobile convergence, explosion of mobile data usage, and multimedia applications, there is a need to test across all layers at once.

No longer merely a convenience service, Wi-Fi technology is now in mission-critical markets, such as healthcare, industrial automation, public safety, and carrier-grade solutions for mobile operators.

This technology is, obviously, here to stay as the primary mechanism for offloading the exploding data traffic. Wi-Fi test equipment is the crucial element that would enable SPs to successfully and flawlessly offload mobile data and multimedia traffic and ensure positive QoE.

Frost & Sullivan

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