SOLUTION PAPER DYNAMIC FREQUENCY SELECTION (DFS) REGULATIONS AND THE IMPLICATIONS TO SERVICE PROVIDERS

Transcription

1 SOLUTION PAPER DYNAMIC FREQUENCY SELECTION (DFS) REGULATIONS AND THE IMPLICATIONS TO SERVICE PROVIDERS

2 Examining how Motorola s MOTOwi4 broadband wireless products utilize automated DFS configuration to simplify implementation, operation and compliance of networks using 5 GHz unlicensed frequency bands worldwide. INTRODUCTION There is good news for wireless broadband providers in the United States and Canada, Unlicensed frequencies at 5.4 GHz are now available for high-speed commercial use. That is good news indeed. With a growing number of countries allowing commercial applications to share the unlicensed 5 GHz frequencies, service providers now have an alternative frequency band to serve more customers and increase revenues, network sustainability and return on investment (ROI). The DFS Mandate All this good news does come with a caveat. It s called Dynamic Frequency Selection, or DFS. Because commercial traffic will be sharing the frequencies with existing radar systems such as military and weather radar operating on Unlicensed National Information Infrastructure (U-NII) channels there are potential spectrum conflicts. Various countries have mandated the use of the DFS protocol to reduce potential interference or interruption of these crucial radar communications. DFS is the solution that resolves these conflicts and makes frequency sharing not only possible, but comfortably workable. Motorola and DFS The Motorola MOTOwi4 wireless broadband product portfolio includes Fixed point-to-point solutions, and Fixed point-to-multipoint Canopy solutions that are ideally suited for use in these frequency bands. Many providers, however, are rightly concerned about the fact that, although DFS functionality is essentially the same, government configuration and compliance mandates differ from country to country. To simplify the complexity of DFS configuration, the wi4 Fixed wi4 equipment provides advanced automation that offers oneclick compliance, no matter where in the world a service provider is doing business. BODY What is DFS? Technically, it is a series of algorithms that facilitate the sharing of U-NII frequencies by commercial and government traffic. Functionally, DFS is a process which alerts the commercial system of a conflicting radar transmission on a given channel. When a DFS-enabled network consisting of master and client or slave devices detects a radar waveform, it triggers a sequence of events that vacates the channel and gives Canopy networks an opportunity to automatically shift commercial traffic to an alternate channel. This allows the radar signal to utilize the original channel without interference or interruption. 2 SOLUTION PAPER: DYNAMIC FREQUENCY SELECTION (DFS)

3 How DFS Works The operation of a DFS-enabled system follows a closely-defined process that is set in motion each time a master device is ready to send a transmission. Channel Availability Check. In the first step of the process, the Master device uses DFS technology to perform a Channel Availability Check before transmitting. Lasting for a specified duration of time (usually one minute), the Channel Availability Check assures that no radar systems are currently operating on the channel. If there is no radar signature detected, the master device signals the client device or devices and transmission begins. Channel Move Time. If the master device detects a radar waveform on the channel, it will not use the channel for transmission. DFS regulations define a Channel Move Time, or the maximum time period devices have to vacate a channel on which a radar signature has been detected. Non-Occupancy Period. To assure uninterrupted radar transmission after a waveform has been recognized on a channel, DFS regulations specify a period of time, called the Non-Occupancy Period, that the channel must remain free of transmission activity, generally 30 minutes. During this time, traffic can be switched over to a pre-selected alternate channel. In-Service Monitoring. During normal operation, even after transmission has begun, a DFS-enabled device performs in-service monitoring of the channel to detect any radar system beginning operation on that channel. Channel Closing Transmission Time. If a radar signature is recognized, the channel is no longer available, and the master device will instruct all associated client devices to stop transmitting on the channel within the DFSspecified Channel Closing Transmission Time. Two DFS Standards Today, there are two main types of DFS standards, each following a similar event sequence. Countries in the European Union, as well as certain other countries, use the European Telecommunications Standards Institute (ETSI harmonized radio standard for unlicensed 5 GHz technology. In the U.S. and Canada, the Federal Communications Commission (FCC) and Industry Canada (IC) have mandated the somewhat different FCC/IC DFS protocol. These two DFS standards are very similar. The major difference has to do with the types of devices required to have DFS capabilities installed. Master and Client Devices FCC/IC DFS regulations define network modules as either master or client devices. Master devices, such as Canopy Access Points (AP) and master Backhaul (BH) modules, use DFS to detect radar waveforms that generate a signal strength above specified DFS detection thresholds. Client devices, such as Canopy Subscriber Modules (SM) and client Backhaul units, do not need DFS capability because they function only after receiving a control signal from the master device. In contrast, ETSI standards for European Union members and other countries specify that all network modules, including subscriber modules, must have DFS systems installed. 3 SOLUTION PAPER: DYNAMIC FREQUENCY SELECTION (DFS)

4 The Canopy 8.2 DFS Solution Canopy 8.2, the newest release of MOTOwi4 Canopy software, provides a DFS solution that enables service providers to meet both types of governmental compliance standards. Canopy 5.4 GHz modules for the U.S. and Canada have Release 8.2 DFS installed. Canopy 5.2 GHz modules sold after July 20, 2007 also ship with Release 8.2 DFS installed. (Canopy 5.2 GHz modules sold before July 20, 2007 may still be deployed and do not need DFS capability.) In the European Union and certain other countries, Canopy 8.2 subscriber modules also have built-in DFS capabilities for compliance with ETSI and other government mandates. Service Provider Concerns Although most service providers are excited about having additional spectrum in which to grow their businesses, there are a few very real concerns about how DFS will affect their network service. In general, there are three major issues network operators face as they operate with DFS in the unlicensed 5 GHz spectrum: Network downtime False positive readings Regional configuration and compliance Motorola has developed the Canopy 8.2 software release to address these concerns and make compliance with DFS regulations simpler and easier. Protection Against Downtime Because DFS requires networks to immediately vacate a channel when a radar signature is detected, there exists a potential for increased network downtime. To help operators avoid this serious and costly challenge, Canopy 8.2 provides Alternative Frequency Selection, which is the capability of selecting two alternate frequencies as backup channels. When a transmission is interrupted by DFS, Motorola software automatically switches the interrupted transmission over to one of the alternate frequencies, helping to assure continued service and end user transparency. Protection Against False Positives Another common cause of network downtime is the false positive reading. DFS systems can and do occasionally detect false positives, misreading certain signals or interference as radar signatures and automatically vacating the channel when, in fact, there is no radar signal. Canopy Release 8.2 has been developed using the latest, most sophisticated technologies and techniques for minimizing false positives, including External Antenna Adjustment. Overly sensitive external antennas can be a major cause of false positive readings. Motorola s Canopy Release 8.2 software automatically adjusts DFS sensitivity for radios with external antennas or reflectors to levels of sensitivity that are neither too high nor too low. Whitening. Canopy 8.2 software includes a tool called whitening, that helps minimize false positive readings by spreading signal power to avoid network selfinterference Whitening works by minimizing peaks that could be interpreted by DFS as radar transmissions, resulting in a significant reduction in false positive readings that interrupt traffic. 4 SOLUTION PAPER: DYNAMIC FREQUENCY SELECTION (DFS)

5 Regional Configuration and Compliance DFS regulations vary by region, frequency band and differing national mandates. That can pose a problem in configuring equipment to comply with the unique DFS standards found in different countries or regions. Service providers are concerned that the manual configuration of equipment for use under different government regulations can become a significant issue in terms of training, cost and time. Canopy 8.2 software solves the problem with leading-edge automation called Region Code that makes conforming to regulations in different countries fast and easy. On a pop-up menu, the provider simply selects the country or region in which the network is operating, and the system automatically configures itself to comply with the operative government mandates. There s no training necessary. Using Region Code capability is fast, uncomplicated and foolproof. In addition, with Canopy Release 8.2, Motorola s Prizm Equipment Management System (EMS) supports remote configuration of network devices via SNMP. Understanding that DFS capabilities and regulations are still evolving, Motorola will continue to provide updated software releases that will include additional regional codes and revised DFS algorithms as the need arises. Protecting Uptime Motorola DFS technology solutions have been developed with the objective of helping wireless service providers maximize network uptime, even when DFS detects radar signatures. By protecting network uptime, Canopy Release 8.2 also preserves all-important service excellence and end user satisfaction. For more information on how Canopy Release 8.2 helps service providers maximize network performance while being in compliance with varying national and regional DFS mandates, call your local reseller or Motorola representative, or visit MOTOwi4 Wireless Broadband Solutions Motorola s MOTOwi4 portfolio of wireless broadband products offers advanced solutions that enable operators to deliver reliable high-speed voice, video and data services in unlicensed spectrum. The MOTOwi4 portfolio gives service providers a range of flexible, mix-and-match, cost-effective options to fit their unlicensed network and business model. Proven in more than 120 countries, wi4 Fixed point-to-multipoint Canopy solutions help providers build and enhance powerful broadband networks using unlicensed and managed spectrum. Our wi4 Fixed point-to-point solutions help bridge and extend high-speed voice and data networks, providing secure, reliable connectivity and services to even the most challenging environments. The MOTOwi4 platform leverages Motorola s more than 75 years of wireless technology knowledge, experience and leadership. Motorola s dedication to creating and maintaining trusted relationships over the long-term also means MOTOwi4 platform users are assured of high levels of worldwide service and support as their networks grow over the years. 5 SOLUTION PAPER: DYNAMIC FREQUENCY SELECTION (DFS)

6 Motorola, Inc. The information presented herein is to the best of our knowledge true and accurate. No warranty or guarantee expressed or implied is made regarding the capacity, performance or suitability of any product. MOTOROLA and the Stylized M Logo are registered in the U.S. Patent and Trademark Office. All other product or service names are the property of their respective owners. Motorola, Inc. 2007