4G网络演进： 4G Convergence from the Bottom Up
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4G Convergence from the Bottom Up
Simon Stanley
Since Arun Sarin, CEO of Vodafone Group plc (NYSE: VOD), called for Long Term Evolution (LTE) and WiMAX to be integrated, providing a single 4G solution for wireless data, not much has happened at the top level; however, integration is already happening at the chip level. As the rollout of LTE begins, base stations, handsets, and CPE equipment will be built using baseband and RF devices that support WiMax and LTE. By the time convergence agreements for LTE and WiMax are made, possible in their next generation, most 4G infrastructure and handsets will use common components.
WiMax has been in development for over 10 years, but the first major deployments of mobile WiMax are just beginning with the Sprint Nextel Corp. (NYSE: S) XOHM Mobile WiMax launch on October 8, 2008, a significant step. LTE is 2 to 3 years behind WiMax, with the specification expected to be complete by the end of 2008 and rollout planned for 2010/2011; however, some vendors are promising system availability before the end of 2009.
Although the IEEE802.16 and WiMAX Forum have approached wireless broadband data from a different angle to 3GPP, much of the technology used for 3GPP’s LTE is similar to that chosen for mobile WiMax. Common technologies include the downstream transmission scheme (OFDM) and the use of multiple antenna (MIMO). By making WiMax baseband and radio frequency (RF) components more flexible and functional, vendors have been able to develop technology demonstrations for LTE and are developing new devices that can be easily configured for either WiMax or LTE.
At this critical time, selecting the correct baseband and RF devices is a key decision for companies developing or deploying 4G base stations, handsets, and CPE equipment. The latest edition of Light Reading's Components Insider explores the different 4G technologies and the highly integrated silicon components now available. The report also includes information on more than 50 baseband and RF components and an analysis of 20 leading vendors.
CPE and handset baseband devices implement the OFDM physical layer (PHY) in hardware or software with DSP cores. Vendors with hardware-based solutions include Fujitsu Ltd. (Tokyo: 6702; London: FUJ; OTC: FJTSY), NextWave Wireless Inc. (Nasdaq: WAVE), Runcom Technologies Ltd. , Sequans Communications , and Wavesat Inc. . Wavesat has begun shipping a DSP-based solution joining Altair International Inc. (Nasdaq: ALTI), Comsys Communications & Signal Processing Ltd. , and Intel Corp. (Nasdaq: INTC). NXP Semiconductors is developing a DSP-based solution that would support most 2G and 3G networks, as well as WiMax and LTE. This group from NXP Semiconductor is now part of the STMicroelectronics/Ericsson joint venture announced in August 2008.
Most base-station baseband solutions are fully programmable using proprietary cores for media access control (MAC), PHY, and networking functions. Leading vendors are DesignArt Networks , picoChip Designs Ltd. , Runcom Technologies Ltd. , and Wintegra Inc. , as well as general-purpose CPU/DSP suppliers Freescale Semiconductor Inc. and Texas Instruments Inc. (NYSE: TXN). All these companies have made a significant investment in production ready software for WiMax, and most are developing software for LTE.
RF front-end devices require a different skill set and technology. In addition to several baseband vendors, analog specialists Analog Devices Inc. (NYSE: ADI), Lime Microsystems, PMC-Sierra Inc. (Nasdaq: PMCS), and Sierra Monolithics Inc. have RF ICs for WiMax and other wireless networks, including LTE. Analog performance is a key differentiator, as is power, footprint, and flexibility. For handsets, RF integration is a key challenge as most RF ICs use 0.18μ SiGe or 0.18μ CMOS rather than the 65nm or 90nm technology used for the latest baseband devices. Several vendors have already addressed this issue by integrating baseband and RF devices on a small module.
The market for 4G chips is changing rapidly with mobile WiMax rollout accelerating and LTE entering the market within the next 12 to 18 months. To maximise revenue, vendors must be flexible, delivering cost-effective solutions today that can scale to support a mix of WiMax and LTE tomorrow. The LTE market is expected to be at least five times the size of the WiMax market, and most vendors cannot afford to miss this opportunity. Whether WiMax and LTE become integrated or not, most of the base stations, handsets, and CPE equipment shipping within the next few years will integrate semiconductor devices that support both technologies.
Simon Stanley, Analyst, Light Reading's Components Insider
4G Chips: WiMax/LTE Technology & Components
WiMax, under development for more than a decade and now growing significantly, has been deployed in many regions as an alternative to wired broadband. Many startups and a few established players are attracted to the WiMax market and are developing integrated semiconductor devices and modules or small systems. Analysts have forecasted hundreds of millions of users within six to seven years; however, there must be further cost reductions and integration at the silicon level for this to happen.
The WiMax semiconductor market is very competitive, with multiple vendors developing both baseband and radio frequency (RF) devices. As Long Term Evolution (LTE) develops and the rollout of WiMax continues, there will be demand for semiconductor devices to support additional frequency bands and a complex mix of frequency, bandwidth, and performance. To meet these challenges, vendors must develop flexible solutions that can meet the performance criteria but still deliver cost-effective and power-efficient designs.
Companies are turning to LTE and finding that many of the key building blocks are the same as WiMax. Many analysts expect the LTE market to be at least five times the size of the WiMax market, which will bring costs down very significantly as volume grows. There is also demand from mobile carriers calling for LTE and WiMax to be integrated to provide a single 4G solution that carriers can sign up for. This has already happened at the silicon level, with vendors working hard to develop flexible solutions that can support both WiMax and LTE.
This report details and analyzes 4G chips and technologies, identifying the key advantages they hold for equipment manufacturers. It also surveys component availability, reviewing features, performance, and flexibility. The report covers more than 50 baseband and RF devices and modules from 20 vendors, and profiles 20 leading vendors in this rapidly growing market.
Mobile WiMax and LTE are the current focus for chipset development. Most devices can also support fixed WiMax installations. The following except shows the devices in a typical WiMax base station or base transceiver station (BTS). On the left is the network interface, in the middle is the baseband including MAC and PHY devices, and then on the right is the RF front end.
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