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<<<Wireless: Keeping the world connected
<Picture: Christian Dupont>By Christian Dupont, regional manager, Americas Wireless Communications Business Unit
Take a look around. In shopping malls, at the beach, in the car -- virtually everywhere you go people are using cellular phones, pagers and other wireless products to keep them connected. And increasingly manufacturers are using digital technology to give these products powerful new features and the extended battery life that make them truly valuable for end users.
For wireless OEMs, the invitation is open. Analysts estimate that the digital wireless market will represent an $8 billion opportunity by 2000 as consumers look for more functionality and features like the Internet and other interactive services in wireless products. More than ever before, Texas Instruments is the IC supplier enabling these advancements in wireless end equipment.
Recently released market analyst reports show that TI is the No. 1 DSP supplier for digital cellular phones worldwide. In fact, of the approximately 48 million digital cellular phones manufactured in 1996, more than half were powered by a TI DSP Solution. TI DSP Solutions are everywhere. A closer look gives some indication of just why so many wireless communications manufacturers are turning to TI for solutions to their next-generation wireless needs.
Digital signal processing
Wireless systems are designed to make communications mobile, so size, weight and battery life are the primary concerns. DSPs cater specifically to these needs with higher integration levels, extremely high performance and low power consumption. TI's customizable single-chip digital baseband platform helps digital cellular phone manufacturers lower component counts, save board space, reduce power consumption, introduce new features, save development costs and achieve faster time-to-market. At the same time, it gives them the flexibility and performance to support any standard worldwide.
Total system solutions
Wireless system design can be extremely complex. This is why it is vital for wireless OEMs to choose suppliers that provide total system solutions, with components optimized from the beginning to work well together. This not only reduces design time but also ensures maximum system performance -- two factors that can make or break a design in the market. In addition to powerful DSP cores, TI is the IC supplier with the capabilities to meet total system needs, from integrated digital and analog baseband sections to radio frequency (RF) and power management functions.
TI's broad product line gives designers all of the silicon and software necessary to take designs to production. And more than just functionality, TI also has the system expertise to deliver solutions optimized for performance and power savings.
Worldwide, world-class support
Perhaps the most telling sign of a committed supplier is the resources it is willing to put behind its customers. TI formed its Wireless Communications Business Unit in 1994 to establish and maintain technology leadership in the fast-growing market. The group focuses specific TI resources on the design, manufacture and support of highly integrated wireless solutions for various popular transmission standards around the world.
As an example, last year TI increased its wireless research-and-development in-vestment, and wireless is one of the key beneficiaries of two other recent TI investments: a $150 million research lab and a $2 billion wafer fab. One product of this dedi-cated business model and research support is the 1-V DSP TI demonstrated at the International Solid State Circuits Conference (ISSCC) in February 1997. With a 10-times reduction in power consumption, this kind of technology improvement is the catalyst for making wireless the new communications model.
Finally, TI is an active force in industry initiatives such as the Communications and Telecommunications Industries Association (CTIA), the CDMA Development Group (CDG) and other standard-related bodies. Together, these groups are working to not only keep up with the wireless market, but to define the services it will provide in the future.
A total supplier
System solutions, system expertise, leading-edge technology and the manufacturing strength to deliver. These are a few examples of the commitment and customer value delivery that have made TI the leading DSP supplier for digital cellular phones. With TI's growing wireless resources and continued commitment, customers can look to TI to help them become leaders in their markets. >>>
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System Integration
A typical implementation of the handset in Figure 1 requires both audio and RF analog-to-digital and digital-to-analog converters (ADCs and DACs), hardware or software signal processing, some kind of control processor, and both active and passive RF components. Since most systems separate baseband and RF, integration tends to occur within each subsystem separately, though the ultimate aim is to integrate as much as possible of the entire system on a single chip. Figure 3 shows how further integration of system components will occur.
Next-generation wireless system integration
<Picture: Figure 3>
Figure 3. Future integration in wireless handsets will occur within the baseband subsystem, among the high-speed digital functions, and in the radio transceiver, where the analog and mixed-signal components are found. Eventually, integration will include all these functions, along with power management, on a single chip.
Baseband
Integration tends to occur within the separate baseband and RF sections, however the ultimate objective is to integrate as much of the current system-component functions as possible into a single chip.
The baseband subsystem includes ADCs and DACs that support both the audio and RF interfaces. These devices are being integrated on one or more components, typically with a number of other functions required to support the designated standard.
The signal processing functions will typically use a combination of a programmable DSP with some functions relegated to a digital ASIC. The bulk of signal processing in TDMA implementations will be done on a programmable device (in the range of 20 to 40 MIPS for current standards), while in CDMA systems the high bandwidth of the spread signal (about 1.23 Mbps for IS-95) requires the use of more hardware.
A high-performance 8- or 16-bit microcontroller is generally used to implement both the protocol processing and user interface functions of the terminal. This software is generally quite complex (requiring from 100 to 500 Kbytes of code space) but is not very processing intensive -- perhaps only 1 to 2 MIPS. It is generally written in C, so compiler efficiency is a key careabout for this component. Some manufacturers have implemented handsets that combine the controller and DSP functions in a single processor in order to reduce parts count and power consumption. However, the small address space of most DSPs and their relatively poor compiler efficiency present difficulties to this approach.
An advanced telephone purchased in today's market will generally have separate audio and RF codecs, one or two programmable DSPs, one or more ASICs, and a separate MCU operating with up to 256 Kbytes of external program memory. Within the next two years, these phones will reduce that part count to a single integrated codec, a DSP and MCU integrated on an ASIC backplane, and external memory. Eventually, memory will also integrated on-chip, and the codec functions will probably be absorbed by the RF transceiver.
Radio Frequency
While tremendous progress has been made in reducing the parts count of the baseband functions of a wireless telephone, not much has happened in the RF arena. The total parts count has been relatively constant at about 300 to 400 for several years. Most of these parts are in the RF subsystem and most are passives -- resistors, inductors and capacitors. Although there are many integrated RF components on the market, cellular manufacturers seem to be choosing tried-and-true, low-cost discrete component designs. The real goal is minimum cost, and unless integration provides minimum cost, phones will continue to have long bills of material. The problem is the economical integration of simple resistors, capacitors and inductors, as well as more complex passives such as surface-acoustic wave (SAW) filters. Of course, integration may reduce the total system cost (including cost savings resulting from a shorter bill of materials and reduced costs of manufacturing and maintenance), even when the actual cost of the bill of materials is higher. Figure 4 shows how the RF section will be integrated in upcoming product generations.
RF integration roadmap
<Picture>Figure 4. The RF section, or radio transceiver, offers many challenges in the economical integration of passive components. >>> |
