Chapter 10: Designing Millimeter-Wave Devices The possibility of using the existing embedded fibers to the curb and neighborhood as well as FSOW tandem links permits broadband back- bone network integration and combined services through a single shared infrastructure, leading to faster deployment and lower system cost for ser- vice providers. Network Operation Center A consolidated network operation center (NOC) for end-to-end network management and control is implemented to relocate the conventional base station control and switching facilities into the NOC to perform the required switching, routing, and service-mixing-function operations. The integration and merging of multiband HFR, FSOW, and digital fiber- optic technologies at the NOC with fixed BWA has provided flexible and unified network operation as well as the possibility of end-to-end network management and control. The consolidation will benefit through lower infrastructure complexity and cost, resulting in a more reliable and cen- tralized database and operations. 273 AP AP Fiber/coax Picocell redistribution: outdoor and/or indoor by wireless, fiber, or coax Building picocell Neighborhood microcell Millimeter- wave links FSOW links Figure 10-2 Integrated hybrid millimeter-wave, fiber, and optical wireless data access and distrib- ution system scenarios. Implementation options for integrated HFR for picocell access and distribution systems for inner city environments and interconnection options. (Note: The World Trade Center towers in New York City are shown in this figure to remember those who died in the terrorist attack of September 11, 2001.) 274 Part 2: Planning and Designing Data Applications Portable Broadband Wireless Data Bridge and Access Node This chapter will now discuss the concept and realization of a portable wireless data access node for a bidirectional ATM-based connection to reach a fixed broadband fiber network. The goal of this effort is to demon- strate the feasibility of a rapidly deployed access node and backbone interconnection to the NOC for application in specialized scenarios, such as military theaters, emergency response, and disaster relief operations. Two portable nodes could also serve as a point-to-point wireless bridge to connect two or more isolated networks in places not served by fibers, as depicted in the lower left corner of Fig. 10-1. Free-Space Optical Wireless Data Access and High-Speed Backbone Reach Extension This is an emerging advanced technology providing many new approaches and platforms for high-bandwidth wireless data access and distribution networks. The technology, in combination with the millimeter-wave net- work topology, has created potential for increased capacity and extended the fiber-based bandwidth and services to users via wireless data. In the demonstrator, an FSOW point-to-point link is employed to complement and extend the NGI wireless data access capabilities for true gigabit-per- second data transport. The combined and side-by-side millimeter- wave/FSOW hybrid network topology shown in Fig. 10-1 provides direct performance comparison with the millimeter-wave links in various envi- ronmental conditions (multipath, rain fade) required for the design and implementation of high-reliability networks. Moreover, this topology ensures a higher degree of link availability when the millimeter wave fails during the rain or the FSOW power budget falls below the specified threshold during foggy weather. It has been shown that the hybrid tech- nology can increase the current millimeter-wave network capacity and high-speed data transport capabilities. A Measurement-Based Channel Model To investigate millimeter-wave propagation issues, a high-resolution channel sounder at the 38-GHz LMDS band to model the channel on the Chapter 10: Designing Millimeter-Wave Devices basis of the measurements and simulation results is used. The model addresses the performance limits for broadband point-to-multipoint wireless data access in terms of data transport capability under realistic commercial deployment conditions. The model is used to examine a broadband channel-adaptive radio modem for dynamic selection of chan- nel quality, channel switching, and bandwidth allocations. Propagation characterization, modeling, and simulation were performed for a short- range BWA system to provide sight selection design rules and solutions for adaptive channel configuration and operation mechanisms. A set of comprehensive data processing tools has been developed that, in combina- tion with the channel sounder, can be used to develop statistical models for the broadband millimeter-wave channels. System Architecture Advantages Compared to the traditional LMDS system, the system technology and heterogeneous network topology previously described possess many tech- nological and operational advantages: Increased coverage and user penetration percentage in each individual cell due to densely positioned users in the service area. This relaxes the tedious effort of cell frequency and polarization reuse planning. This in turn leads to a simpler design of overlapping cells for higher coverage and permits more efficient utilization of the spectrum. The required AP hub and customer transmitting power (at millimeter wave) are immediately scaled down (15 dB minimum) because of the relatively short cell radius. The result is a low-power, low-cost system solution and less complex MMIC hardware design. A major reduction in system interference (adjacent channel and adjacent cell) comes from constraints and limitations imposed by the power amplifiers’ nonlinearities in high-power systems, due to spectral regrowth. As a result, possible reduction in the required radio channel spacing can be achieved, leading to increased system capacity due to higher spectrum utilization and efficiency. The near-short-range directly projected line-of-sight (LOS) propagation path becomes free from “major” multipath interference, intercell interference, and obstructions (buildings, moving objects, trees, and foliage). Consequently, the propagation path loss approaches that of square law, leading to a power-efficient system. 275 276 Part 2: Planning and Designing Data Applications An additional improvement in the system gain margin (7 to 10 dB) and link availability comes from the short LOS distance that removes the signal reception limitation due to excessive rain attenuation and system downtime experienced in higher-power, longer-range LMDS systems. The utilization of a hybrid millimeter-wave/FSOW network topology extends the broadband network reach without utilizing the radio spectrum. It can also provide high-capacity links, increased frequency reuse of millimeter waves, and greatly enhanced network reliability and availability. 1 Implementation and Test Results Now, let’s look at the implementation of experimental BWA links and an asynchronous transfer mode (ATM)–based networked testbed infrastruc- ture for experimentation toward high-speed Internet applications and W-WLL performance evaluation. The testbed comprises a single AP and three user nodes (two fixed and one portable), as shown in Figs. 10-3 and 10-4, operating in the 5.8/28/38-GHz bands. 1 A side-by-side high- speed point-to-point FSOW link (see Fig. 10-1), in parallel or tandem, was also implemented to extend the backbone fiber bandwidth to the AP operating up to 622-Mbps rates. On all the links, network demonstra- tions have been carried out for mixed services: broadcast 80-channel Internet User A ODU Satellite broadcast receiver Video Network operations center User B ODU User A IDU Combined data and video Video User B IDU Data Decoded 32-QAM data Access point Fiber-optic connection Data 28 GHz 28 GHz 38 GHz Figure 10-3 Multiband multiuser BWA testbed configurations. Chapter 10: Designing Millimeter-Wave Devices video and RF wireless data channels with speeds at 1.5-, 25-, 45-, and 155 (OC-3)–Mbps rates in 4-, 16-, 32-, or 64-quadrature amplitude modula- tion (QAM) formats. The key issue in the topology described here is that the AP transmitter has the low power practical for mass deployments. The implemented portable node of Fig. 10-4 is equipped with an OC-3 connection that occupies 50 MHz of bandwidth for 16 QAM. The perfor- mance of the OC-3 portable node was also field-tested using a data stream supplied by either a bit error test set or an Internet advisor ATM analyzer. Error-free operation was achieved in a 20° sector of a 470-m microcell environment. Figure 10-5 depicts the functional elements and interconnection in the ATM-based BWA and distribution network in the NOC. 1 The ATM switch is programmed to combine and distribute traffic, integrate mixed services, and create dynamic user interconnection paths. The combined ATM wire- less data/fiber network operation, as well as service integration, has been evaluated and tested using an Internet advisor ATM analyzer. Error-free millimeter-wave/optical transmission and network operation were achieved for 155-Mbps data channels switched between three users in cells up to 470 m in radius. Figure 10-6 illustrates several examples of integrated HFR and RF photonics for wireless data/fiber internetworking and interface options. 1 The advantage of microwave and RF photonics is that it not only expands and merges broadband distribution and access, but it also incor- porates “networked” functionality and control into the wireless data links. The top figure indicates integration of several different wireless 277 Rcv Trx FSOW MMW Trx Portable node • OC-3 duplex transmission • Separation between nodes = 470 m • Transmit power = –10 dBm • BER < 10 –9 • Link established within 20° of hub antenna LOS • Configuration suitable for point-to-multipoint operation Portable and FSOW nodes Hub unit on hillside 0510 Angle from boresight (degrees) 15 20 Power received at portable node Received power (dB) –40 –30 –20 –10 0 Figure 10-4 Portable node experi- mentation and mea- sured BER. 278 Part 2: Planning and Designing Data Applications data bands (PCS, NII, millimeter-wave, FSOP) into a single HFR using WDM technology. The system integration has also been demonstrated for a single optical wavelength and synchronized multicarrier millimeter- wave radios with modular IF stages. The millimeter-wave subcarriers are selected with one-to-one fiber/wireless data channel mapping to provide unified end-to-end network operation and continuity. The lower left part of Fig. 10-6 depicts the role of HFR for multiple AP signal distribution, centralized control of individual antenna beam and phases, and frequency band selections. Here, the otherwise tradi- tional “antenna remoting” function has been replaced by a multiple ser- vice access link with centralized network management and control. The lower right part of Fig. 10-6 depicts yet another example—utilizing the HFR technology to distribute high-stability, low-phase-noise local oscillator (LO) and sync signals to the millimeter-wave up/downconverters in the APs and base terminals. The experimentally deployed LO distrib- ution demonstrated lower harmonics and superior phase quality in millimeter-wave systems, as well as lowered electrical intermediate fre- quency (IF)/RF terminal design complexity, component counts, and over- all cost compared to pure all-electrical solutions. A two-channel (12- and 16-GHz) photonic unit was demonstrated for evaluating the perfor- mance of a switched dual-band photonic link in distributing LO/sync sig- nals. The scheme provides the flexibility of frequency tuning, channel selection, and dynamic bandwidth allocations for wireless data access systems. OC3 OC3 OC3 Modem ModemModem Portable hub Modem Modem Modem Hub EO/OE EO/OE OC3 OC3 Hub Portable node ATM Ethernet hub 5.8-GHz wireless LAN NOC and control center UTP ATM DS3 Multi-IF HFR connection To backbone ATM NOC Users SM to MM converter Figure 10-5 A three-user testbed and ATM network topology. 279 MMW ISM NII PCS Access radios Multi-users in single or multiband Radio on fiber hub Multi- band RCVs Laser array ␭ mux Network operation center WDM fiber network ROF and hybrid fiber radio internetworking topology Mixed analog and digital signals and mixed ser vice capabilities AP AP AP Broadcast services Local Switched beam antenna Broadband interactive services Wireless routers IP router Beam steering LO gen Hybrid fiber radio • Distributed antenna remoting • Reception from multiple picocells • Photonic up/down conversion • Coherent combining using photonics X LO X 3 A N T A N T Mixer Mixer Data on subcarriers Filter 2 GHz x12 Laser Antenna 8-GHz LO Demux • Large multiplicative phase noise • Difficult filtering requirements • Design complexity • Independent LOs in system • Lower phase noise • Coherent LO distribution • Simplified filtering • Centralized functional management Data on subcarriers Figure 10-6 Multiband ROF and HFR interconnection examples for a unified end-to- end network. Top: the role of WDM and RF photonics in a wir eless data/fiber network interface. Lower left: multiple AP signal distribution and contr ol. Lower right: central- ized high-stability low-phase-noise LO distributed to the APs and base terminals. 280 Part 2: Planning and Designing Data Applications Conclusion This chapter has introduced and demonstrated a short-range LOS LMDS-like millimeter-wave and FSOW architecture for a BWA system that possesses many technological and operational advantages. These include ease of installation and alignment; low radiation power; and, effectively, a link free from major multipath, obstructions (trees, build- ings, and moving objects), and adjacent cell interference. The chapter also presented several system architecture and implementation scenar- ios for a complementary millimeter-wave/FSOW system highly suitable for integration of a BWA network with the existing backbone fiber net- work. The proposed system architecture is suitable for deployment in a highly developed, densely populated, urban inner city environment where large-capacity broadband services are in great demand, but lacking wired broadband access infrastructure. References 1. Hossein Izadpanah, “A Millimeter-Wave Broadband Wireless Access Technology Demonstrator for the Next-Generation Internet Network Reach Extension,” IEEE Communications Magazine, 445 Hoes Lane, Piscataway, NJ 08855, 2002. 2. John R. Vacca, Wireless Broadband Networks Handbook, McGraw-Hill, 2001. 3. John R. Vacca, Satellite Encryption, Academic Press, 1999. 4. John R. Vacca, i-mode Crash Course, McGraw-Hill, 2001. Wireless Data Services: The Designing of the Broadband Era 11 CHAPTER 11 Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. 282 Part 2: Planning and Designing Data Applications Loose coalitions of tech geeks, amateur radio hobbyists, and social activists worldwide have begun to design free broadband wireless data networks. 3 Sit in a park or cafe near one of these networks with your laptop and modem, and you can access files on your home or office com- puter, or access the Web without a hard-wired connection. While some of these broadband wireless data networks are designed to extend free Internet access to people who otherwise couldn’t afford the service, others are building what amounts to a community intranet. It’s not about Internet access. It’s about building up a broadband wire- less data network, connecting people through their computers in the community. The broadband wireless data networks are based on the 802.11b wire- less data networking standard. Participants purchase access points, then create or buy antennas and place them on the roofs of their houses or apartment buildings and become nodes on a broadband wireless data network that links members’ computers together. Many members with antennas already have high-speed data lines, such as DSL or cable modems, and they can share that Internet access for free with anyone who has an 802.11b modem and is within range of an access point. (The Glossary defines many technical terms, abbreviations, and acronyms used in the book.) A growing number of local businesses will raise antennas and join the broadband wireless data network as a way to establish a presence among the other users of the network. A couple of coffee shops in Seattle are already part of SeattleWireless’ data network, which so far has nine nodes. As more people join the broadband wireless data network, the com- munity grows and gives more impetus for businesses, for example, to maintain sites on the community network for free. Instead of paying a recurring monthly fee for a Web site, members incur only the one-time cost of putting up an antenna and linking to the broadband wireless data network. Other businesses may want to add nodes on the broadband wireless data network so workers can access the corporate network from home or nearby cafes or restaurants. The broadband wireless data network doesn’t have to hit the public Internet, and can use virtual private network tech- nology to tunnel securely into the corporate intranet. The independent way the broadband wireless data networks grow, however, may be one of the drawbacks. [...]... i-mode Crash Course, McGraw- Hill, 2001 6 John R Vacca, The Cabling Handbook, 2d ed., Prentice Hall, 2001 CHAPTER 12 U.S.-Specific Wireless Data Design Copyright 2003 by The McGraw- Hill Companies, Inc Click Here for Terms of Use 300 Part 2: Planning and Designing Data Applications The General Packet Radio Service (GPRS) is a next-generation packet data service that provides wireless data connectivity... packet data Figure 12-1 depicts typical data transfer rates that compare GRPS with currently deployed wireless data networks.1 301 TYPICAL 9 .6 KBPS Figure 12-1 110 THEORETICAL DATA TRANSFER RATE TYPICAL TRANSFER RATE RANGE BASE DATA TRANSFER RATE DATA TRANSFER RATE IN KILOBITS PER SECOND (KBPS) 10 20 30 40 50 60 70 80 90 100 Typical data transfer rates THEORETICAL 19.2 KBPS TYPICAL 4.8 TO 8 KBPS DATATAC... KBPS TYPICAL 9 .6 TO 14.4 KBPS CDPD GSM CIRCUIT-SWITCHED THEORETICAL 171.2 KBPS TYPICAL 14.4 TO 115 KBPS GPRS WIRELESS DATA NETWORK 120 130 140 150 160 170 180 302 Part 2: Planning and Designing Data Applications Currently deployed wireless data networks such as CDPD, Mobitex, and DataTac operate at speeds of up to 19.2 kbps Current circuitswitched data services on GSM networks operate at 9 .6 kbps, while... of future wideband wireless data systems References 1 Sheila S Hemami, “Robust Image Communication over Wireless Channels,” IEEE Communications Magazine, 445 Hoes Lane, Piscataway, NJ 08855, 2002 2 “A Hardware Multichannel Simulator for Wideband Wireless Systems,” Microwave Journal, 68 5 Canton St., Norwood, MA 02 062 , 2002 3 John R Vacca, Wireless Broadband Networks Handbook, McGraw- Hill, 2001 4 John... kbps Peak Throughput Classes 1 Up to 1000 8 2 Up to 2000 16 3 Up to 4000 32 4 Up to 8000 64 5 Up to 16, 000 128 6 Up to 32,000 2 56 7 Up to 64 ,000 512 8 Up to 128,000 1024 9 Up to 2 56, 000 2048 across the GPRS network during the remaining lifetime of an activated communication context Once again, the network may limit the subscriber to the mean data rate even if additional transmission capacity is available... circuit-switched data (HSCSD) trials conducted in Europe have shown data rates of up to 64 kbps It is expected that typical GPRS networks will support data transfer rates that range from 19.2 to 115 kbps The data transfer rate will depend on the individual carrier’s allocation of resources This means that a typical GPRS network could have transfer rates over 5 times faster than those possible over the wireless data. .. added to the faded signal Typical wireless data test systems require transmitter, channel, noise, and receiver, so a combined noise source and fading channel simplifies the test setup PROPSim C8 Figure 11-8 Antenna array application CHANNEL 1 RX1 CHANNEL 2 RX2 CHANNEL 3 RX3 CHANNEL 4 RX4 CHANNEL 5 RX5 CHANNEL 6 RX6 CHANNEL 7 RX7 CHANNEL 8 RX8 TX 297 Chapter 11: Wireless Data Services Figure 11-9 Multiple... that can tolerate infrequent data loss 3 Non-real-time, error-sensitive application that can tolerate data loss This is the classification that is associated with SMS and GMM/SM 4 Real-time traffic, error-sensitive application that can tolerate some data loss 5 Real-time traffic, error-insensitive application that can tolerate data loss 3 06 Part 2: Planning and Designing Data Applications TABLE 12-4... across the Global System for Mobile Communication (GSM)2 and IS-1 36 timedivision multiple-access (TDMA) wireless data networks It also complements existing services such as circuit-switched data and short message service (SMS) With over 500 million subscribers today, the GSM mobile communication standard is the leading digital wireless data communication standard in the world The size of the current... CHANNEL 3 TX4 CHANNEL 4 TX5 CHANNEL 5 TX6 CHANNEL 6 TX7 CHANNEL 7 TX8 Figure 11-10 MIMO system TX1 CHANNEL 8 ⌺ RX PROPSim C8 TX1 CHANNEL 1 RX1 CHANNEL 2 CHANNEL 3 RX2 CHANNEL 4 CHANNEL 5 RX3 CHANNEL 6 CHANNEL 7 RX4 TX2 CHANNEL 8 Conclusion This chapter provides an introduction to a variety of techniques used to provide robust image transmission over wireless data channels Controlled redundancy can . Broadband Networks Handbook, McGraw- Hill, 2001. 3. John R. Vacca, Satellite Encryption, Academic Press, 1999. 4. John R. Vacca, i-mode Crash Course, McGraw- Hill, 2001. Wireless Data Services: The Designing. users via wireless data. In the demonstrator, an FSOW point-to-point link is employed to complement and extend the NGI wireless data access capabilities for true gigabit-per- second data transport Planning and Designing Data Applications Portable Broadband Wireless Data Bridge and Access Node This chapter will now discuss the concept and realization of a portable wireless data access node for