Ultra Wideband Implementation Issues – Site 2
July 4th, 2007
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By Mark Bowles (Founder & Vice President of Business
Development & Marketing at Staccato Communications)
A key element of UWB is the use of MultiBand-OFDM technology that transmits data simultaneously over multiple carriers spaced apart at precise frequencies. Some inherent benefits of MB-OFDM include high spectral flexibility and resiliency to RF interference. Given the unlicensed nature of the UWB spectrum, in which many wireless devices must coexist, enhanced spectral flexibility is an important factor that enables MB-OFDM to comply with local requirements by dynamically turning off certain tones or channels in software.
A key element with UWB is flexibility – for both spectrum-usage and chip-level implementation. Multi-band UWB using MB-OFDM allows the same hardware device to be dynamically fine-tuned in software in order to comply with different regulatory environments around the globe. In addition, the inherently digital nature of MB-OFDM with a relatively small amount of analog circuitry makes it possible to implement complete solutions in CMOS without requiring exotic Compound III-V processes such as Silicon Germanium.
From a robustness standpoint, it is also useful to note that OFDM technology has been proven in other high-performance, widely deployed communications systems including, Wi-Fi 802.11a/g, WiMAX 802.16a, HomePlug and global ASDL standards. For wireless implementations like UWB, OFDM also offers important advantages in that it is very energy-efficient allowing the receive function to capture very small amounts of energy, even in relatively noisy RF environments. This makes it ideal for implementing UWB within a mobile handset alongside 3G wireless communications.
Initial product developments have focused primarily on Band Group 1 of the UWB specification, which uses the spectrum from 3.1 to 4.8 GHz. This allows for cost effective implementation of complete solutions that are based on existing CMOS geometries while simplifying the design of radio and analog front end circuitry. The 3.1 to 4.8 GHz frequency band is ideal for supporting three sub-bands of 528 MHz each, as shown below
Frequency Allocation for UWB Bandgroup 1
Certified Wireless USB is already specified for Band Group 1, however as UWB development ramps up in Europe, the focus is shifting toward Band Group 3, which uses spectrum from 6.3 to 7.9 GHz. Therefore, from a chip selection standpoint, it will be important for developers to standardize on chip-level architectures that can immediately support today’s requirements, while also being capable of extending to encompass spectrum in the higher Band Groups.
Chip size and form factor are also important considerations, especially with the trend toward smaller and thinner mobile handset implementations. As always, cost and power consumption are other key related factors. These objectives are best addressed through the use of a single-chip, all-CMOS approach, which minimizes size, cost and power usage from the outset and also pays dividends in more efficient production capabilities throughout the market ramp-up and maturation phases. In contrast, suppliers that start out with multi-chip implementations and/or exotic processes like SiGe, BiCMOS or GaAs tend to face a significant and often difficult transition at some point in order to bring down their costs and reduce design complexity. From a development efficiency and production ramp-up standpoint, it just makes good sense to start as close as possible to where you need to end up.
Using advanced Wafer Chip Scale Packaging (WCSP) techniques, an all-CMOS design can be combined with associated functionality, such as passives, filters, crystals, and other elements of the wireless interface. The result is a complete and ready-to-use, single-chip UWB node in a form factor as small as 7.5 by 7.5 mm square and only .7 mm thick, which is ideal for implementing UWB within today’s small, thin handsets.
System integration is also streamlined through the use of a protocol-independent kernel software approach, which allows simultaneous operation of Certified Wireless USB, Bluetooth and Wi-Net, without forcing developers to write additional code for each protocol. Likewise, built-in chip-level support for 128-bit AES encryption is an important element for implementing security for the UWB interface. Other system integration requirements include support for standard buses such as SDIO, GPIO, USB, etc. as well as embedded software tools and libraries for invoking standard features. The key objective needs to be empowering handset designers to seamlessly integrate UWB alongside other functions, while keeping their focus primarily on the overall functionality of the handset.
Handset-Centric Usage Models
UWB in every handset will enable users to activate a “10 meter bubble” of flexible, wireless auto-discovery that moves with them anywhere they go, ready to connect with applications in their immediate proximity, based upon their user-defined security and auto-connect settings. Depending on the settings, users can be automatically alerted whenever they come into proximity of enhanced services offered by mobile operators or their partners. Based on specific revenue and service models, UWB technology can be used along with multiple protocols to either connect users-to-users or users-to-services, as shown below.
Emerging Handset-Centric Applications
With multi-protocol UWB able to simultaneously support Certified Wireless USB, Bluetooth and WiNET IP traffic, mobile phone handsets can unify communications between the traditional USB-oriented PC ecosystem and other wireless environments.
As the internal storage capacity of mobile handsets continues to grow and multimedia becomes a routine aspect of consumer applications, the ability to casually interface handsets to larger displays will also become an important differentiator. UWB offers the flexibility and bandwidth for handsets to interface directly with larger displays, such as TVs, PCs or projectors.
UWB will also create exciting new opportunities for applications using handset-to-handset communications, such as Personal Area Social Networking (PASN). PASN is a natural outgrowth of social networking, which already has become the hottest trend on the Internet, as shown by the success of sites such as mySpace, facebook.com, YouTube, LinkedIn, Xanga.com, eHarmony, miniClip, classmates.com, etc. By leveraging the auto-discovery capabilities of UWB-enabled handsets, PASN applications will inject a “personal touch” into existing social networking applications, enabling users to easily find and connect with one another while on the go. New revenues for mobile operators will come from a combination of PASN subscriptions, transaction fees and advertising, as well as charges for integrating with existing online Social Network providers.
As handset performance increases and the above application scenarios proliferate, an increasing number of users will come to see their wireless handsets as “mobile personal servers”. The trend toward smartphones combining voice, PDA functionality, email, web browsing, cameras, and MP3 players is already laying the groundwork for this transition. However, most consumers still see these mobile devices as secondary to their primary computing environments.
The ability to not only pack more functionality into the mobile handset but also to seamlessly “get it out” for interaction with multiple environments will turn the handset itself into the primary computing environment for many users. For instance, rather than carrying a laptop everywhere, users can simply bring their UWB-enabled handset into proximity of any UWB-enabled keyboard/mouse, display and printer to immediately establish Wireless USB connections for a fully functional working environment. No need to synchronize files or applications between multiple computers because everything moves right along with the user.
In addition, because the handset-as-personal-server model can interact with any set of peripherals and leaves no residual personal footprints, it provides a natural pathway for mobile operators and their service partners to offer “landing stations” for mobile users. Whether in an airport, coffee shop, hotel room or virtually any other transient environment, users could simply sit down at a UWB-enabled peripheral station with their handset in their pocket and be able to seamlessly work as if they were in their own home or office. To make it even more transparent for the user (and more lucrative for the mobile operator) all of the usage-tracking and billing would most efficiently be handled through the user’s primary handset carrier.
The final major application area that will be fueled by the high-bandwidth and flexibility of UWB-enabled handsets is the phone-to-access point services model. Unlike WiFi hotspots, kiosks or other models that require users to take an action to connect with the local environment, users can pre-set their UWB-enabled handsets for casual connections through auto-discovery of any information that might interest them. For instance, during the few minutes that a user is standing in line at a coffee shop they can be alerted to the latest album release from one of their favorite artists, make a purchase decision and have it downloaded before they even get to the head of the line. With UWB’s high bandwidth, they could even download a full length feature film or the latest episode of their favorite TV show within just a few minutes.
For local business owners and service providers, the auto-connectivity, high bandwidth and short-range of UWB wireless allows the creation of “walled garden” environments in which transient users can access multiple channels of locally controlled content – such as streaming audio, video, or other localized information (news, weather, events, etc.). The revenue generation models can range from advertising to downloads to pay-for-access. Once again, as primary service providers for the users’ handsets, mobile operators are likely to play a central role in usage-tracking and billing for many of these point-of-access service scenarios.
Summary
The ability to pack additional performance, memory and functionality into handsets, combined with the fact that mobile phones are the one device that everyone carries, creates a ready-made opportunity for handsets to emerge as the single device that integrates everything.
By designing UWB wireless capabilities into every handset, using cost-effective, low-power, single-chip CMOS UWB multi-protocol solutions, handset designers are laying the foundation for this new generation of handset-centric value-added applications. Ultimately, the widespread use of UWB wireless will give mobile operators the flexibility to seamlessly link their users with virtually any local environment and will give users the freedom to be at the center of their own world no matter where they are.
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Site 1 – About UWB Design for Handset Applications |
By Mark Bowles |
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Entry Filed under: UWB Articles
Related Information and News:
NXP Innovation Brings SDR Technology to Address Mobile Communication Standards
About UWB Design for Next-Generation Handset-Centric Applications – Site 1
UWB Wireless Technology Is Changing Local Device Interaction
UK´s Ofcom proposed to make UWB Equipment Regulations (Exemption)
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