IEEE 802.11n delivers maximum video performance in wireless entertainment applications
Feb 1, 2006
By Gil Epshtein A new breed of wireless entertainment network must provide higher bit rates to support the distribution of multiple-quality video and HTDV streams from a central location, along with total home coverage. These video applications cannot tolerate bandwidth fluctuations. Therefore, guaranteed bandwidth and quality of service (QoS) are essential requirements in order to provide wire-like performance regardless of changing environmental conditions....
RF MEMS in mobile phones
Sep 1, 2005
By Refugio Jones and Mark Chapman The need for multiband, multimode band switching at low insertion loss
while maintaining excellent linearity in mobile phones is driving the need for
RF MEMS-based switches. Since this switching problem gets even more acute
as new complex waveforms, such as WiMAX are added to this mix, this article
looks at the current state of development in RF MEMS switches and discusses
its impact on 3G cellular phones....
Single-chip, multimode WEDGE RF transceiver for 3G handsets
Sep 1, 2005
Sequoia Communications has combined its polar architecture with 0.18 micron silicon germanium (SiGe) biCMOS process technology to create what it claims is the first true multimode transceiver using a common basic architecture across all modes....
Low-power receiver architecture for interference-robust UWB radio
Aug 1, 2005
By Domine M.W. Leenaerts and Jozef R.M. Bergervoet Ultra-wideband (UWB) wireless communication promises unprecedented levels of seamless connectivity between consumer electronics devices, enabling gigabytes of data to be transmitted in seconds rather than hours without exhausting the batteries of hand-held devices. To meet the low-cost requirement of consumer product applications, the multiband-orthogonal frequency-division multiplexing system has been designed to minimize transceiver architecture complexity....
Direct-conversion Bluetooth receivers
Jul 1, 2005
By Mark Lane Direct-conversion receivers have well-known challenges that are difficult to overcome such as dc offset. Due to the large modulation bandwidth, the effect of frequency offsets is negligible on the overall performance of the direct conversion receiver as implemented in Bluetooth....
Measuring single-tone desensitization for CDMA receivers
May 1, 2005
By Jinku Kim and Dave Devries This article sheds light on two important contributors to single-tone desensitization in CDMA receivers; namely reciprocal mixing and cross-modulation. It also presents a practical low-cost method for measuring single-tone desensitization performance in a CDMA receiver....
Design considerations for an ultra-compact GSM radio solution
May 1, 2005
By Mike Durrant and Andreas Nitschke The design of modern, cellular handsets places even more stringent requirements on the transceiver portion. Although the radio part of the handset is divorced from the user interface by sophisticated software, it is nonetheless absolutely essential to the satisfactory operation of the handset....
DVB-H architecture for mobile communications systems
Apr 1, 2005
By Stuart Pekowsky and Khaled Maalej The availability of new low-power, small form-factor digital video broadcast hand-held (DVB-H) demodulator and silicon tuner solutions now enable the reception of digital TV signals on hand-held devices where small displays and limited battery power are a fact of life. The requirement for improved video display functionality and support for multimedia applications makes DVB-H an attractive complementary technology to existing 3G in-band solutions....
Designing wireless interfaces for patient monitoring equipment
Apr 1, 2005
By Noel Baisa Recent advances in wireless technologies now make it possible to free patients from their equipment, allowing greater freedom and even making possible monitoring by their health provider while the patient is on the go....
Direct digitization using superconducting data converters
Mar 1, 2005
By Jack Rosa Direct digitization is the ultimate enabler for future wireless communications. It
refers to the ability to bring the digital domain as close to the antenna as possible, on both the receive and transmit ends of the radio transceiver system. It's a goal that remains just out of reach for systems based on traditional semiconductor technology and conventional data converters. Through the use of superconducting microelectronics technology and new, high-performing analogto-digital and digital-to-analog converters, however, direct digitization is firmly in reach....
Direct modulation radio hardware architectures for 3G communications systems
Feb 1, 2005
By Patrick Naraine The base station transceiver system is one of the most expensive network elements in the wireless network infrastructure and directly impacts the cost of the overall network design and deployment. The requirement for increased capacity and higher data rates will inevitably lead to increased cell deployments. To maintain costs at an acceptable level, telecommunications equipment
manufacturers will continue to seek more cost-effective solutions to their
infrastructure hardware....
CDMA2000 Design and Performance Requirements
Feb 1, 2005
By Bill Schofield and Brad Brannon Various heterodyne solutions have continued to flourish through incarnations of
transceiver designs, each generation adding new control loops or components to improve the architectures. While communications standards such as CDMA2000 provide challenging performance requirements, the trends are for deep cost reduction, highly integrated solutions and flexibility....
Designing a ZigBee-ready IEEE 802.15.4-compliant radio transceiver
Nov 1, 2004
By Khanh Tuan Le Besides highlighting the physical (PHY) and MAC
layers of the IEEE 802.15.4 standard, and the network, security and application
layers of the ZigBee wireless technology, this article focuses on efficient
implementation of IEEE 802.15.4-compliant radio-on-a-chip by identifying
potential low-power features in the standard, suitable transceiver architectures
and considering standard CMOS design issues....
Power supply and ground design for WiFi transceiver
Nov 1, 2004
By Roger Bremer, Tracey Chavers, Zhongmin Yu A solid RF layout requires careful planning of board stack-up, power supply routing, supply bypassing, and grounding. These techniques, along with correct placement of filter components, can address PLL spurs as demonstrated by an IEEE-902.11a/g transceiver reference design....
Comparing windows for multitone suppression
Nov 1, 2004
By Raghavendra G. Kulkarni Harmonic interference suppression requires windows with fast decaying sidelobes. When the requirement is to keep peak sidelobes low, Harris windows are preferred; but when the mainlobes are to be of minimum widths, the recently published Kulkarni windows offer a good choice....
