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Fujitsu's Mobile WiMAX Solutions / Advanced Technology and Application of H.264/AVC

FSTJ 2008-7 Cover Image

2008-7 (Vol.44, No.3)

Special Issue 1: This issue covers the developed products, the proud technologies that differentiate our system, standardization activities, and some application scenarios devised by members of the global collaboration team.

Special Issue 2: In recent years, the need has been felt for a coding system with an even higher compression ratio than that of MPEG-2. In this special issue, we introduce the results of Fujitsu's R&D efforts toward solving this problem from the viewpoint of providing a common platform suitable for new services and solutions that meet the needs of the H.264/AVC market.

2008-7 (Vol.44, No.3) Contents
Special Issue 1: Fujitsu's Mobile WiMAX Solutions

1. Preface (471 KB)
The information and communications technology (ICT) environment is moving towards ubiquitous and user-centric systems. Since mobility is the essential requirement for such systems, wireless communication systems are taking on greater roles. This issue covers the developed products, the proud technologies that differentiate our system, standardization activities, and some application scenarios devised by members of the global collaboration team. ---[Toshitaka Tsuda, Senior Vice President, Fujitsu Laboratories Ltd.]

SoC solutions

2. Fujitsu's Challenges for WiMAX System-on-a-Chip Solutions (1.08 MB )
Worldwide Interoperability for Microwave Access (WiMAX) is a promising candidate for providing high-data-rate mobile broadband access systems around the world. This paper describes specific features of Mobile WiMAX, such as scalable orthogonal frequency division multiple access (OFDMA), adaptive modulation and coding, and smart antenna technologies, a system configuration, candidate applications, and our challenges for WiMAX system-on-a-chip (SoC) solutions. ---[Tamio Saito, Makoto Awaga, Takeshi Takano]
3. Digital Baseband SoC for Mobile WiMAX Terminal Equipment (848 KB)
We have developed a digital baseband system-on-a-chip (SoC) that conforms to the next-generation wireless communication standard, Mobile WiMAX, for mobile terminals. This SoC consists of the physical layer (PHY), lower media access control layer (LMAC), and dual processors. The PHY carries out multiple-input multiple-output (MIMO) processing and orthogonal frequency division multiple access (OFDMA) modulation and demodulation. The LMAC implements cryptography functions and controls frame-level data transactions. The dual processors are used for MAC layer processing to achieve high data throughput with a low clock frequency. The PHY and LMAC offer a maximum data reception of 45 Mb/s at an operating frequency of 44.8 MHz, and for the SoC including the firmware, we obtained a prediction of achieving 45 Mb/s. Regarding power consumption, the SoC dissipates 252 mW during 15-Mb/s downlink data reception. ---[Miyoshi Saito, Masahiro Yoshida, Makoto Mori]
4. Novel Compact RF Module for Mobile WiMAX Terminal Equipment (951 KB)
This paper describes a radio frequency (RF) module for Mobile WiMAX, where low cost, low power consumption, and small size are needed. To satisfy these requirements, we developed a new micro-size RF module and a new RF CMOS LSI using 90-nm CMOS technology. The RF module supports downlink multiple-input multiple-output (MIMO) technology and includes RF-LSIs, a power amplifier, a voltage-controlled temperature compensated crystal oscillator, and band-pass filters. Its size is 15 mm x 15 mm x 1.5 mm. This new RF module is the smallest in the world and includes all of the RF circuits necessary for Mobile WiMAX. The 2.5-GHz frequency band is supported and the RF bandwidths are 5 and 10 MHz. (WiMAX Forum profile: 3A.) This paper presents the RF architecture and high-frequency circuit technology used for the RF-LSI and RF module. The advantage of the RF module is that design engineers can easily get high-quality RF performance without special RF knowledge. ---[Kazuhiko Kobayashi, Shinji Saito, Kimitoshi Niratsuka]
5. System and Reference Design Kits for Mobile WiMAX Terminals (789 KB)
We have developed a system design kit (SDK) and reference design kit (RDK) for Fujitsu's Mobile WiMAX chipset. These kits will be useful and effective for customers evaluating the chipset and developing products with it. This paper outlines the hardware and software of the SDK and RDK and introduces their performance in development fields and the market. ---[Takayuki Arai, Shoji Yamamoto, Tomozumi Saigo]
6. Power Consumption Control Technology in WiMAX MAC Layer (590 KB)
Reducing the power consumption of mobile stations (MSs) is one of the major issues for wireless broadband systems. The Mobile WiMAX standard defines Idle and Sleep modes to reduce MS power consumption by suspending the operation of the MS. In addition, this standard defines a protocol that enables the MS's transmitting power to be controlled from the base station. However, manufacturers should consider how to implement these modes and a protocol for using them. In this paper, we describe mechanisms for implementing the Idle and Sleep modes in an MS using the functionality of the media access control (MAC) layer. We also describe a novel transmission power control algorithm that can reduce power consumption. ---[Kohei Iseda, Tetsumei Tsuruoka, Tsuguo Kato]

Device technologies

7. Continuous-Time Sigma-Delta ADC in 1.2-V 90-nm CMOS with 61-dB Peak SNDR and 74-dB Dynamic Range in 10-MHz Bandwidth (919 KB)
This paper describes a continuous-time sigma-delta (CTSD) analogue-to-digital converter (ADC) with 14-bit resolution, and a full-scale input of 1.0V p-p differential. The circuit is implemented in an 8-layer 90-nm 1.2-V CMOS process. Integrated into the macro is a low-jitter clock generator (LC-PLL). The macro is configurable to allow various oversampling ratios and signal bandwidths, which makes it suitable for multi-band applications such as WiMAX. The CTSD ADC provides the advantage of low power, requires no anti-aliasing filter, and is immune to noise outside the ADC bandwidth. The CTSD architecture uses a third-order single-loop sigma-delta with a 4-bit quantiser. Continuous background calibration is used to tune the quantiser thresholds and digital-to-analogue converter (DAC) currents. A prototype of the CTSD macro has been taped out and measured. It has a peak signal-to-noise-plus-distortion ratio (SNDR) (ENOB = 9.8) of 61 dB and dynamic range of 74 dB in a 10-MHz bandwidth and requires only 31 mW per channel. ---[David Enright, Ian Dedic, Gavin Allen]
8. Wide-Range Low-Noise Fast-Hopping Fractional-ΣΔ Synthesizer in 1.2-V 90-nm CMOS (901 KB)
A 90-nm CMOS wide-band low-noise fast-hopping synthesizer for 1.2-V supply and integration into a WiMAX front-end is described. The synthesizer's voltage controlled oscillator (VCO) is designed for a wide spread of process parameters and a guaranteed frequency range from 2.766 to 3.253 GHz. This target performance is achieved by using a highly sophisticated digital control unit, invoking fast automatic calibration of up to 24 fixed frequencies after power-on, and featuring fast digital calibration correction of approximately 20 μs upon a frequency change. A further feature that allows stable operation in widely varying environmental conditions (e.g., a temperature change of 140˚C) is a second control loop of the phase-locked loop, using the frequency correction signal to a second VCO control input. An improved digital algorithm for fast frequency tracking is used, and this speeds up the digital tracking decision by a factor of 13 or more. In the final phase of the locking procedure, the same algorithm delivers multilevel phase measurement, enabling faster locking and improved (in terms of noise, linearity, and reference leakage) phase detection. ---[Walter Marton, Bernd Germann, Robert Braun]


9. Standardization Activities for Mobile WiMAX (667 KB)
The WirelessMAN standard developed by the IEEE 802.16 Working Group (WG) on Broadband Wireless Access Standards for wireless metropolitan area networks is commonly referred to as the specification for the Mobile Worldwide Interoperability for Microwave Access (Mobile WiMAX) system, but this is not exactly true. The WirelessMAN standard developed by IEEE 802.16 WG includes detailed specifications and various optional functionalities so that it can cover various usage scenarios such as ones ranging from fixed access to mobile access and may extend system performance. The Technical Working Group of the WiMAX Forum selects suitable functionalities and parameters from IEEE 802.16 specifications for the Mobile WiMAX scenario. Discussion in IEEE 802.16 WG is carried out by individual experts, while that in the WiMAX Forum is carried by industrial delegates. Therefore, there are some differences in the standardization activities in IEEE 802.16 WG and WiMAX Forum. Technically sound contributions are more important for standardization in IEEE 802.16 WG, while much weight is put on industrial interest in the WiMAX Forum. This paper briefly reviews the relationship between these two standardization organizations and describes Fujitsu's activities concerning them. ---[Michiharu Nakamura, Takafumi Chujo, Tamio Saito]
10. Multihop Relay Extension for WiMAX Networks — Overview and Benefits of IEEE 802.16j Standard (1.22 MB )
In 2006, the IEEE 802.16 Working Group (WG) approved a Project Authorization Request (PAR) focused on the Relay Task Group (TG). The main task of this Relay TG was to develop an amendment to the IEEE Std. 802.16 enabling the operation of relay stations (RSs) in OFDMA wireless networks defined by 802.16. In September 2007, the Relay TG completed the first phase of its work, getting the WG's approval for the first draft. The final approval of this amendment is expected to take place during the second half of 2008.
This paper presents the theoretical benefits and performance evaluation of relaying technology used in WiMAX wireless systems, providing insight into the rationale behind the main features adopted by the Relay TG. We describe how four different types of RSs can be implemented using different feature sets, each one optimized for a different deployment scenario. Based on the theoretical benefits and performance evaluation results, we focus on the RS type showing the most promising performance, which is the non-transparent RS operating in distributed scheduling and security mode, and outline its operation. ---[Masato Okuda, Chenxi Zhu, Dorin Viorel]

Infrastructure and Network planning

11. Dimensioning and Cost Analysis of Multihop Relay-Enabled WiMAX Networks (853 KB)
WiMAX networks are intended to cover diverse clutter categories with a higher data range and throughput compared with 2G/3G networks. This paper explains an approach to the analytical dimensioning and possible planning techniques for a cellular network based on IEEE 802.16j technology. The main emphasis is on the methodology used for evaluating the cell edge coverage extension of the base station using a relay station. The paper also highlights the economical feasibility analysis of WiMAX network deployment with and without support for relay stations. ---[Bharathi Upase, Mythri Hunukumbure]
12. Simulation Study of Fractional Frequency Reuse in WiMAX Networks (780 KB)
WiMAX is a metropolitan area network (MAN) wireless technology that provides high-quality broadband services to mobile users. For maximum usage of the available spectrum, each cell should operate on the whole available bandwidth. However, this leads to unacceptable interference for cell edge users and reduces the coverage. This paper reports on a study of fractional frequency reuse (FFR) in WiMAX networks, which is a promising approach for reducing interference at the cell edge. Simulation results show that FFR can provide significant coverage gains by reducing the cell edge interference while retaining high utilisation of the spectrum. FFR can therefore be regarded as an essential technique for interference management in WiMAX networks. ---[Luciano Sarperi, Mythri Hunukumbure, Sunil Vadgama]
13. Mobile WiMAX Base Station Architecture and RF Technology (744 KB)
In March 2008, Fujitsu issued a press release about its commercial product of a Mobile WiMAX base station (BS) "BroadOne WX300", which is an all-in-one type of very small outdoor equipment, composed of a mobile IP network interface, IEEE 802.16e air interface and radio transceivers.
This base station has two transceivers in a cabinet and supports one 20 MHz or multiple 10 MHz channel bandwidths per transceiver by reconfiguring it with a software download. In addition, this platform is the same as an outdoor RF unit for the two-box separate type, which is an indoor baseband processing unit and the outdoor RF unit configuration.
In this paper, we introduce our achievements regarding this base station, which use highly efficient RF high-power amplifier technology, as a very small outdoor unit, and the base band technology for the benefit of efficient use of frequency. ---[Naoyuki Saitou, Yoichi Endo, Yasuhiro Shibuya]
14. Development of High-Efficiency GaN-HEMT Amplifier for Mobile WiMAX (565 KB)
Base stations for Mobile Worldwide Interoperability for Microwave Access (WiMAX) will require much higher power efficiency to dramatically reduce the increase in power consumption. High-efficiency amplifiers with high gain will be required to decrease the power consumption of the base stations. Gallium nitride high electron mobility transistors (GaN-HEMTs) have been attracting a lot of attention as high power amplifiers because of their high breakdown voltage characteristics. This paper describes the development of a highly efficient GaN-HEMT for the high-efficiency amplifiers. First, gate length and unit gate width were designed to improve gain performance. The key feature for improving efficiency was found to be the electrical trap characteristics. Drain efficiency of 50% with adjacent channel leakage ratio of less than -50 dBc was obtained with Mobile WiMAX signals, resulting in a small base station. ---[Toshihide Kikkawa, Taisuke Iwai, Toshihiro Ohki]

Special Issue 2: Advanced Technology and Application of H.264/AVC

15. Preface (477 KB)
In recent years, the need has been felt for a coding system with an even higher compression ratio than that of MPEG-2. In this special issue, we introduce the results of Fujitsu's R&D efforts toward solving this problem from the viewpoint of providing a common platform suitable for new services and solutions that meet the needs of the H.264/AVC market. With the aim of creating new services that make use of HDTV and broadband networks, Fujitsu will continue to provide outstanding products and perform fundamental R&D under the catchphrase "Fujitsu for Image Processing". ---[Kiichi Matsuda, Fellow, Fujitsu Laboratories Ltd.]
16. Fujitsu's Approach to H.264/AVC and Application Trends (706 KB)
This paper outlines H.264/AVC features and application trends, describes implementation problems and technology developed by Fujitsu to solve these problems, and introduces H.264/AVC products developed by Fujitsu. The H.264/AVC video coding system — which achieves more than twice the compression ratio of the existing MPEG-2 standard — became an international standard in 2003 through the joint efforts of ITU-T and ISO/IEC. Its high-performance features are making it attractive for a wide array of applications from mobile communications to HDTV. Nevertheless, there are many problems that must be solved in the development of practical H.264/AVC systems such as an encoding complexity ten times that of MPEG-2 and the difficulty of coding control. To address these problems, Fujitsu has developed an original coding control algorithm that achieves low encoding complexity and high picture quality while capitalizing on a compression ratio twice that of MPEG-2. This original technology is being used in the development of H.264/AVC-compliant products for a wide range of fields taking advantage of Fujitsu's technical expertise ranging from device to network technologies. ---[Akira Nakagawa]
17. H.264/AVC HDTV Video Codec LSI (648 KB)
Fujitsu has developed a video codec LSI for the compression/decompression of high-definition television (HDTV) video in conformance with the H.264/AVC standard, which is expected to become the next-generation video compression standard. This LSI uses a "prefetch memory control technique" that reduces external memory access — an important issue in the compression of HDTV video — by 25 to 45% in terms of data transfer rate compared with conventional memory access techniques. It achieves superior picture quality and low power consumption by optimal application of video-encoding algorithms accumulated by Fujitsu over many years. The LSI is embedded with two of Fujitsu's original low-power memory units (fast cycle random access memory [FCRAM]) in a single package under the product name MB86H50. The entire chip including memory consumes only about 600 mW during audio-visual (AV) encoding of HDTV video, achieving low power consumption at an industry-leading level. With the above features, the MB86H50 can record, play, and transmit HDTV video at high quality via a wide variety of equipment including portable AV devices, hard disk recorders, and home network appliances. ---[Hiroshi Nakayama, Yasuhiro Watanabe, Akihiro Higashi]
18. H.264/AVC Codec System for IP Networks (664 KB)
The start of digital terrestrial broadcasting and the popularization of widescreen TV have initiated a recent shift in video content to the high-definition (HD) format. Meanwhile, thanks to high-speed, low-cost networks, video distribution services via IP networks have become more familiar. Also, the recent needs for collecting and delivering HD video contents with a large data volume via low-cost IP networks have become more conspicuous.
To address these demands, Fujitsu has developed a video codec called IP-9500 based on the latest video coding technology H.264/AVC that enables more than twice the data compression ratio compared with conventional coding technology. This product is the world's first example of commercializing real-time transmission of HD video contents via IP networks. This paper describes the IP-9500, which leads to the realization of versatile visual solutions domestically and internationally. ---[Yasushi Umezaki, Michiko Mizoguchi, Hideki Miyasaka]
19. Audio Coding Algorithm for One-Segment Broadcasting (596 KB)
With the recent progress in coding technologies, a more efficient compression of video and audio data has become available, resulting in popularization of new services such as one-segment broadcasting and content delivery. In 2003, ISO/IEC developed the latest MPEG audio standard called High-Efficiency Advanced Audio Coding (HE-AAC). Based on the conventional Advanced Audio Coding (AAC) algorithm, HE-AAC features a higher compression ratio than that of AAC. Because the total bit rate of one-segment broadcasting is as low as about 400 kb/s including video, audio, and other data, the bit rate for audio must be reduced as much as reasonably possible in order to increase the bit rate for video. Fujitsu has developed a new HE-AAC encoding algorithm that provides high sound quality at a lower bit rate of 32 kb/s while the bit rate of the current one-segment broadcasting is 48 kb/s. This paper describes the technology to improve the sound quality of the HE-AAC encoder and demonstrates its advantages based on the results of subjective listening tests. ---[Masanao Suzuki, Yasuji Ota, Takashi Itoh]