Electronic Design

Communications> Cell Phones

March Of The Cell Phones

With cell subscribers in the U.S. numbering 152 million, virtually every adult and a large percentage of teens own cell phones. The cell phone has become the most common and popular way to communicate. Sure wired phones are still in place, but their number will no doubt decline as we continue the wireless revolution. Today, more than 1.5 billion cell-phone subscribers span the globe, with China being the country with the largest number of users-250 million and growing. Growth percentage over the past several years hovered in the low double digits, most of that being fueled by the Asian market. The U.S. shows a lower growth rate, mainly because it's a replacement or upgrade market as current subscribers buy new phones with color screens, cameras, and faster data services.

The cell-phone business is still in multistandard mode, with GSM dominating at about 70% worldwide and CDMA in its many flavors continuing to gain share. Eventually, CDMA cell phones will become ubiquitous, and CDMA IP companies like Qualcomm are no doubt working hard to make that happen as soon as possible. In the meantime, especially in the U.S., carriers are continuing to support all older technologies, including analog and NA-TDMA, while adding or upgrading their GSM and CDMA systems.

As for the shift to third-generation (3G) systems, it has yet to happen in any volume. Systems in the U.K. and Asia are operational, but with only a small number of users. Carriers of 3G are hurting due to the paucity of 3G handsets, and potential 3G carriers are delaying implementation to help spread the enormous new infrastructure and spectrum costs over a longer period.

Many think that the Wi-Fi invasion will hurt 3G. However, just as many also feel that the technologies are compatible and not directly competitive. We could see 3G/Wi-Fi phones that permit a subscriber to use one data service or another, depending on location and circumstances. We'll certainly get Wi-Fi/GPRS/EDGE PCMCIA cards that give laptops hot-spot access and cell-phone capability. Then there's the forthcoming IEEE 802.20 standard. Eventually, this proposed new system will bring packet-based voice and data services to mobile customers with rates to 1 Mbit/s at speeds up to 250 km/hr.

Work is already underway on 4G systems. Japan's NTT DoCoMo has developed 4G systems based on variable spreading factor orthogonal frequency and code division multiplexing (VSF-OFCDM), which produces data rates at 10 times the 3G maximum of 2 Mbits/s. Such a rate will make streaming video, music, gaming, and graphics even more popular applications on future phones.

On top of all that activity, cell-phone systems continue to evolve. Deployment of 2.5G systems forges on, along with the related data services. E911 will soon be a common feature in new phones. And local number portability, which began November 24, 2003, means that subscribers can move from one carrier to another without changing their number. Also, they may transfer their home wired number to a cell phone. How many take advantage of these generous options remains to be seen, but it certainly will affect the fortunes of cell-phone carriers. Ultimately, it could lead to a serious decline in the legacy wired telecom carriers.

On the technology side, look for increased integration of cell-phone circuitry. The proposed new DigRF standard, which defines an interface between the RF and baseband chips, should bring designers the benefits of mixing and matching chips from different vendors. More chips will move to full CMOS implementation, but there will still be some SiGe and biCMOS in most phones.

Finally, look for a continuing reshuffling of the leading handset vendors. Today, Nokia, Motorola, Samsung, Siemens, and LG Electronics dominate, in that order. But with the original-design-manufacturer (ODM) model becoming common and the rocketing growth in China, we can expect some new companies to join that prestigious list in the near future.

TOP TEN

  • Color screens and cameras entice subscribers to upgrade. Sexy new phones keep sales in the U.S. strong, rather than a rush of new subscribers. Color screens are a huge success, and so are the built-in cameras. Now that fast data services are available, phones can easily transmit color still photos and limited time video.
  • Smaller, more highly integrated phones. Size still matters and for cell phones less is more. The phones are forever shrinking, with chip makers working hard to reduce the number of chips required to implement a phone. However, that rides in direct conflict with the need to add new features and gadgets. To that end, two chip designs are emerging with a single RF chip and one big baseband chip that supports all of the latest color screen, cameras, and higher-speed data modes.
  • Roll out of 2.5G data phones. With 3G not yet arriving, faster 2.5G technologies are becoming more available. GPRS for GSM is already widely available. But now EDGE is rolling out across the country, giving a data capability to 150 kbits/s. The faster EV and EV-DO technologies for cdma2000 are also available. These technologies will meet our data-transmission needs until 3G finally shows up, probably in 2005. Meanwhile, data services will ramp up. You can now get e-mail, instant messaging, short-message service, and multimedia message service over some networks. Those features will continue to expand, though, as more basestations upgrade to the faster data modes.
  • Battery power is the weak link. As more and more features and services are added to cell phones, power consumption will escalate. Much progress has been made in batteries and power management, yet all of these developments can't overcome the huge power increases from the color screens and other features craved by subscribers. While lithium-ion battery manufacturers tweak their designs to improve efficiency, it may not be enough. The portable fuel cell may be the answer, but it's still too large and heavy to be universally accepted by consumers. Handset manufacturers will be challenged to make the right tradeoffs in the power versus features war.
  • Push-to-talk is hot. Walkie-talkie push-to-talk (PTT) half-duplex operation has been available for years thanks to Nextel, which adopted Motorola's technology to add this feature to cell phones. Now, interest and demand is spreading. Verizon recently announced its version of a PTT system and a Sprint version is soon to arrive. PTT is one of those features that hooks you after using it for the first time, especially if you work in a field or environment that demands instant access to another person. Old-style two-way radio "over and out" techniques still work well.
  • Cell phones may be hazardous to your health. We've all heard the "cell phones may be hazardous to your health" warning. Back in the mid to late 1990s, there were a number of scares attributing excessive cell-phone usage with brain cancer. After some attempts to confirm this, the general consensus was that cell phones were basically harmless. Yet, the threat has never gone away. Now a new U.S. research effort is underway to find out once and for all if the problem is real. One solution is to use a headset. But many use Bluetooth links, which are also RF but much lower in power than the cell-phone transmitter. It's just like many of the other scares: excessive use of anything will eventually cause problems.
  • Local number portability (LNP) is happening. As of November 24, 2003, you can switch carriers and still keep your old cell number. It could be expensive if you have to buy another phone, and there's always the hassle of transporting any files you may have stored on the old phone. Carriers can also charge you for such a conversion, and you may have to pay to get out of your contract. Most carriers will fight to keep you as a subscriber, so don't jump until you check out the perks they're offering to stay aboard. Look for the carriers to launch some legal action to roll back this requirement.
  • Wired to wireless number portability also a possibility. The FCC also proclaimed that you can transfer your current wire-line number to a cell phone if you wish to cut the cord completely. This has the cell-phone carriers even more upset than LNP. It may result in a significant loss of revenue if many subscribers make the switch. With some carriers already losing wire-line business to VoIP phones via cable TV companies, it's scary to contemplate the financial impact.
  • Multistandard basestations moving to SDR. Basestations will continue to support multiple modes and bands for years to come. A software-defined radio (SDR) in the basestation can help to combat this issue, as it can accommodate any and all standards with the right software. Fast analog-to-digital converters with sampling rates to 250 Msamples/s and DSP software are now available to replace the hodgepodge of today's equipment. Look for smart antennas to further improve the utilization of existing basestations in spite of the forever-changing standards.
  • E911 on the way but not here yet. Most carriers now have their firm plans for implementing the Enhanced 911 location service that must go into effect by the end of 2005. CDMA basestations will use an enhanced GPS solution, while GSM basestations will employ the time-difference-of-arrival (TDOA) triangulation system. CDMA phones will contain a GPS receiver that reports the user's location. GSM phones don't need any additional circuitry; just a software upgrade. At the basestation, new TDOA equipment will spot a phone's location within 100 feet or less. While some users will fuss over the loss of privacy inherent with this new system, others will welcome the safety and security it delivers.
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