Friday, April 26, 2013

WLAN System Design Fundamentals Part 1: General Concepts Hear No RF Evil - See No RF Evil

WLAN System Design Fundamentals Part 1: General Concepts Hear No RF Evil - See No RF Evil

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WLAN System Design Fundamentals Part 1: General Concepts

Posted: 26 Apr 2013 08:36 AM PDT

With much talk about small cells, a review of wireless LAN (WLAN) design is in order. This review is a basic design guide for WLAN coverage enhancement, the first of a multipart series on in-building wireless enhancement.

The Wi-Fi Alliance, the organization that owns the Wi-Fi (registered trademark) term specifically defines Wi-Fi as any WLAN product based on the Institute of Electrical and Electronics Engineers’ (IEEE) 802.11 standard. Some folks think WiFi technology is not part of a "small cell". However, one can argue that unless a wireless technology is part of a tower's local infrastructure, it is considered a small cell. A WLAN design includes "small cells" of wireless access points (WAP) much like a cellular DAS. Even if a carrier adds "WiFi offloading" the WLAN is detached from the tower and hence could be described as a small cell.

Typical complex Wireless LAN architecture by Cisco

Typical complex WLAN architecture by Cisco

The demands on WLANs for functionality and scalability are growing due to the rapid proliferation of new network devices and applications. The number of devices and connections per user is steadily increasing. It is common for most users today to not only have a primary computing device but also at least one other smart device. Wireless operators have worked hard to accommodate the increased demand for data services over wireless networks. They have been forced to consider alternative offload strategies, including wirelessly connecting electronic devices (Wi-Fi). Unfortunately, the majority of smartphones being introduced into the marketplace only support Wi-Fi at 2.4 Gigahertz (GHz), which is rapidly increasing pressure on Wi-Fi designers and administrators to design products for the smallest segment of bandwidth available. Many devices now include the 5 GHz band (vis-à-vis 802.11n). Administrators and IT Managers are finding themselves faced with the challenge of providing ever-increasing levels of WLAN service in areas where simple coverage is the singular design goal. While there have been great advances made in the speed and ease of implementation of Wi-Fi networks, the basic nature of radio frequency (RF) is generally unchanged. Increasing the number of users who can access the WLAN in a small physical space remains a challenge. The steps and process for a successful high user density WLAN design that can be proven, implemented, and maintained.

General Process for Wirless Local Area Network (WLAN) Design

The general concepts underlying medium-density Wi-Fi design remain true for many environments. But it is important to note that the content and solutions presented here will not fit every WLAN design scenario. Rather, the intent of the design guide is to explain the challenges in WLAN design and to offer successful strategies so that engineers and administrators understand them and are able to articulate the impact of design decisions.

Not treated here, but of potential concern in some situations and jurisdictions, is the matter of radio frequency safety. In general, power density from most WLAN installations is sufficiently low as to be acceptable under most codes and standards. However, the designer should always examine and provide for these possibilities.

WLAN design refers to any environment where client devices will be positioned in office environments where coverage expectations of a normal enterprise deployment, in this case a traditional, multi-floor, carpeted office are both ubiquitous and robust. For reference, a typical office environment has indoor propagation characteristics for signal attenuation as shown below. User density is a critical factor in the design. Aggregate available bandwidth is delivered per radio cell, and the number of users and their connection characteristics (such as speed, duty cycle, radio type, band, signal, and signal-to-noise ratio) occupying that cell determines the overall bandwidth available per user. A typical office environment may have APs deployed for 2,500 to 5,000 square feet with a signal of -65 dBm coverage and a maximum of 15 to 20 users per cell. That is a density of one user every 100 square foot (sq. ft.) and yields a minimum signal of -65 dBm.

WLAN 2.4 GHz Coverage Heat Map (WAPs are white-shaded circles; Coverage scale is received signal power)

WLAN 2.4 GHz Coverage Heat Map (WAPs are white-shaded circles;
Coverage scale is received signal power)

Before a WLAN design is completed, a heat map survey and RF spectrum measurements are performed. A WLAN survey detector as well as a spectrum analyzer can reveal both existing WAPs and any interference that may be present in a facility. Graphical heat maps help visualize anticipated wireless LAN behavior for planning and design of a new or upgraded system.   During the survey general information on the architectural characteristics of an office should be noted. A sample of existing AP signals is collected while spectrum readings are made to support the study and analysis.

Propagation of electromagnetic waves inside buildings is a very complicated issue. There are various models based on various principles with various requirements for input data complexity. In real situations, any piece of furniture, open doors and windows, moving people, reflections from outside the building and other effects influence the signal propagation. In a propagation study, several assumptions are made based on either typical WLAN equipment parameters including AP power output and average antenna gain. Predicted coverage levels on an individual multiple input multiple output (MIMO) WLAN channel may vary up to plus or minus several Decibels (dB) due to antenna gain variations in azimuth. The WLAN signal also changes due to attenuation of the walls and ceiling. Assuming a median attenuation for both frequency bands, wall losses are also estimated based on the survey and empirical data. Heavy wall losses are modeled as moderate cement member unit losses. Floor to floor penetration is modeled as the floor construction is assumed to be concrete poured on a metal pan. However, with some signals penetrating the floors, coverage will be enhanced with AP parameter optimization. Exterior wall and window losses are modeled as based on survey observations and other empirical data. It is also assumed that the 802.11n AP's will be operated in narrow channel mode (i.e. 802.11b) so that multiple channels can be utilized for frequency division multiplexing of users. The design criteria are -65 dBm in coverage under a load of 15 users. A typical office may have APs deployed for 2,500 to 5,000 square feet with a signal of -65 dBm. However, to the end, typical AP layout goal is to assure contiguous coverage throughout all of the building.

In summary, WLAN design fundamentals include planning, analysis and design of the heat map data, RF spectrum background noise levels and propagation characteristics of the building. WLAN AP layout is only effective after these steps so that excellent coverage for 802.11n technologies will be available to all users in the building. A WLAN upgrade may be necessary at your facility to ensure business needs are met with technology- business drives technology!

 


About the author:

Chris Horne, Chief Technology OfficerChris Horne is Chief Technology Officer with the LBA Group, Inc. Chris is a Professional Engineer, and holds a Doctorate in Electrical Engineering.

He specializes in wireless and industrial communications, including DAS system design and evaluation, RF safety, and RF interference management. Chris has successfully undertaken many challenging WLAN and DAS projects. Contact Chris at chris.horne@lbagroup.com or 252-757-0279.

 

 


About LBA Group Inc.
LBA Group
LBA Group, Inc. has 50 years of experience in risk management, design, and integration of industrial and wireless telecommunications infrastructure assets, worldwide. It is comprised of the professional engineering consultancy Lawrence Behr Associates, Inc. LBA University, Inc. providing on-site and online professional training; and LBA Technology, Inc., a leading integrator of radio frequency systems, lightning protection, and EMC equipment for broadcast, industrial, and government users. The companies are based in Greenville, N.C., USA.

Keep up with the latest LBA news and industry information on Facebook at: www.facebook.com/LBAGroup.

The post WLAN System Design Fundamentals Part 1: General Concepts appeared first on LBA Blogs.

Tuesday, April 16, 2013

LBA’s Lawrence Behr Named SBE Fellow Hear No RF Evil - See No RF Evil

LBA’s Lawrence Behr Named SBE Fellow Hear No RF Evil - See No RF Evil

Link to LBA Blogs

LBA’s Lawrence Behr Named SBE Fellow

Posted: 16 Apr 2013 08:46 AM PDT

LBA Group's Lawrence Behr Named SBE Fellow at April 8 NAB 2013 Meeting
SBE's Board elected Behr to receive its highest honor and plans to recognize the industry innovator at its National Awards Dinner Oct. 30, 2013.

Click here to view the press release.

 LBA Group's Lawrence Behr Named SBE Fellow

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Friday, April 5, 2013

Six Steps to Understanding HazCom GHS Compliance Hear No RF Evil - See No RF Evil

Six Steps to Understanding HazCom GHS Compliance Hear No RF Evil - See No RF Evil

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Six Steps to Understanding HazCom GHS Compliance

Posted: 05 Apr 2013 02:06 PM PDT

A fast approaching deadline means all chemical exposed workers must be trained in The Revised Hazard Communications Standard Safety Data Sheets (HazCom GHS) in order to be OSHA compliant. Most of these workers aren't in the chemical industries. They are carpenters who handle adhesives, tower workers who handle paints, and many more trades.

The magnitude of the task is vast – some 5 million employers must train 43 million workers to the new OSHA standard by deadline! To help you understand the new regulations, LBA University™ offers this six-step guide on HazCom GHS compliance.

OSHA Safety for business, workplace & Life

1.   What is the new GHS OSHA standard and when does it begin?

The Globally Harmonized System (GHS) is a globally standardized approach to label elements and safety data sheets. The basis of GHS encompasses practices utilized by major existing systems around the world, including OSHA’s Hazard Communication Standard and the chemical classification and labeling systems of other U.S. and international agencies.

The new standard provides harmonized classification criteria for health, physical, and environmental hazards of chemicals. It also includes standardized label elements that are assigned to these hazard classes and categories, and it provides the appropriate signal words, pictograms, and hazard and precautionary statements to convey the hazards to users. A standardized order of information for safety data sheets is also provided.

OSHA is adopting the GHS.  This means the Hazard Communication Standard (HCS) is being modified. The original standard is performance-oriented, allowing chemical manufacturers and importers to convey information on labels and material safety data sheets in whatever format they choose. The GHS utilizes a more standardized approach to classifying the chemical hazards and conveying the information.

The new GHS OSHA standard will include detailed criteria for determining what hazardous effects a chemical poses, as well as standardized label elements assigned by hazard class and category. The safety data sheet requirements establish an order of information that is standardized. Adoption of the GHS in the U.S. and around the world aims to improve the understanding of chemical information received from other countries. The goal is to elevate the effective and efficient access to information by all those exposed to chemicals, including emergency responders.

The revised HazCom GHS will be phased-in using several key compliance deadlines in the U.S.   The table below outlines these deadlines and the actions necessary for compliance. 

Compliance Effective Date Requirement(s) Compliance Responsibility
December 1, 2013 Train employees on the new label elements and safety data sheet (SDS) format. Employers
June 1, 2015
December 1, 2015
Compliance with all modified provisions of this final rule, except:The Distributor shall not ship containers labeled by the chemical manufacturer or importer unless it is a GHS label  Chemical manufacturers, importers, distributors and employers
June 1, 2016 Update alternative workplace labeling and hazard communication program as necessary, and provide additional employee training for newly identified physical or health hazards. Employers 
Transition Period to the effective completion dates noted above May comply with either 29 CFR 1910.1200 (the final standard), or the current standard, or both Chemical manufacturers, importers, distributors, and employers

Three key compliance facts:

  • Employers must provide the appropriate HazCom GHS compliance training prior to the compliance effective date.
  • Employers are required to be in compliance with either the existing HCS or the revised HCS, or both.
  • OSHA understands that there will be a period of time where labels and SDSs under both standards will be present in the workplace. This will be considered acceptable, and employers are not required to maintain two sets of labels and SDSs for compliance purposes.

The bottom line for meeting compliance standards for the December 1, 2013 deadline is that employers must train employees on the new label elements, which include pictograms, hazard statements, precautionary statements, signal words and the new SDS format. This training must take place prior to the effective date.

2. How has the standard changed from the old HazCom?

Three major areas of change:

  • Hazard definitions have been changed to provide specific criteria for hazard classification of health and physical hazards, as well as classification of mixtures.
  • Chemical manufacturers and importers will be required to provide labels that include a harmonized signal word, pictogram, and hazard statement for each hazard class and category. Precautionary statements must also be provided.
  • Safety Data Sheets will now have a specified 16-section format.
All workers encountering chemicals in the workplace must be trained.

All workers encountering chemicals in the workplace must be trained.

3. What are the details of the new HazCom GHS pictograms and labels?

Under the current HazCom, the label preparer must provide the identity of the chemical, and the appropriate hazard warnings. This may be done in a variety of ways, and the method to convey the information is left to the preparer. Under the revised HazCom, once the hazard classification is completed, the standard specifies what information is to be provided for each hazard class and category.

Labels will require four elements:

  • Pictogram: A symbol plus other graphic elements, such as a border, background pattern, or color that is intended to convey specific information about the hazards of a chemical. Each pictogram consists of a different symbol on a white background within a red square frame set on a point (i.e. a red diamond). There are nine pictograms under the GHS. However, only eight pictograms are required under the new HazCom.
  • Signal words: A single word used to indicate the relative level of severity of hazard and alert the reader to a potential hazard on the label. The signal words used are “danger” and “warning.” “Danger” is used for the more severe hazards, while “warning” is used for less severe hazards.
  • Hazard Statement: A statement assigned to a hazard class and category that describes the nature of the hazard(s) of a chemical, including, where appropriate, the degree of hazard.
  • Precautionary Statement: A phrase that describes recommended measures to be taken to minimize or prevent adverse effects resulting from exposure to a hazardous chemical or improper storage or handling of a hazardous chemical.

There are eight required HazCom GHS pictograms and they must be displayed with the symbol in black and bordered in red as illustrated below:

HCS Pictograms and Hazards

OSHA chart

*The environmental pictogram is not required, because environmental hazards are not within OSHA's jurisdiction.

Note: HazCom GHS will require chemical manufacturers, importers, distributors, or employers who become newly aware of any significant information regarding the hazards of a chemical to revise the labels for the chemical within six months of becoming aware of the new information. Labels on containers of hazardous chemicals shipped after that time must contain the new information. If the chemical is not currently produced or imported, the chemical manufacturer, importer, distributor, or employer shall add the information to the label before the chemical is shipped or introduced into the workplace again.

4. How will HazCom GHS change the Safety Data Sheet (SDS)?

The information required on the safety data sheet (SDS) will remain essentially the same as that in the current standard known as HazCom 1994. What will change is the format for how that information is displayed.  The revised Hazard Communication Standard for the SDS format is the same as the ANSI standard format which is widely used in the U.S. and is already familiar to many employees.

The SDS format will require 16 sections with specific headings in a specific order:

  • Section 1. Identification
  • Section 2. Hazard(s) identification
  • Section 3. Composition/information on ingredients
  • Section 4. First-Aid measures
  • Section 5. Fire-fighting measures
  • Section 6. Accidental release measures
  • Section 7. Handling and storage
  • Section 8. Exposure controls/personal protection
  • Section 9. Physical and chemical properties
  • Section 10. Stability and reactivity
  • Section 11. Toxicological information
  • *Section 12. Ecological information
  • *Section 13. Disposal considerations
  • *Section 14. Transport information
  • *Section 15. Regulatory information
  • Section 16. Other information, including date of preparation or last revision

*The contents of sections 12-15 will not be enforced, but the section headings must be included. The contents of these sections are not under OSHA's jurisdiction.

Millions of workers must be trained by 1 December 2013!

Millions of workers must be trained by 1 December 2013!

5. Who is affected and what are the benefits and cost?

According to estimates published by OSHA, over 5 million workplaces and 43 million employees in the U.S. would be affected by HazCom GHS. The standard for determining what facilities are affected is relatively straightforward. The United States Department of Labor states that any establishment where employees "could be exposed to hazardous chemicals" is required to comply with OHSA HazCom GHS.

OSHA has projected several benefits from the revised HCS.  The agency said that on an annual basis it will result in the prevention of 43 fatalities and 585 injuries and illnesses, 203 lost-workday injuries and illnesses, and 64 chronic illnesses. This translates into preventing 318 lost-workday injuries and illnesses. OSHA estimates that the monetized value of this reduction in occupational risks is an estimated $250 million a year.

OSHA estimates substantial residual financial benefits as well.  They believe that productivity improvements for health and safety managers and logistics personnel will result in savings of $475.2 million. The total cost for implementing and maintaining HazCom GHS is estimated at $201 million a year on an annualized basis for the entire U.S.

6. How to stay current on the latest training requirements?

As with any government mandated safety requirement, it is subject to change. HazCom GHS is no exception. It is expected that the GHS will certainly issue changes over time that may be adopted on a two year cycle.

Updates in the future could include:

  • Technical updates for minor terminology changes
  • Direct Final Rules for text clarification
  • Notice and Comment rulemaking for more substantive or controversial updates such as additional criteria or changes in health or safety hazard classes or categories. Visit www.osha.gov/dsg/hazcom for detailed GHS HazCom information.

 


LBA university logo

LBA University™ is happy to serve as a resource for your questions concerning HazCom GHS. Bryan Dixon, LBAU's course director, is an OSHA-certified safety instructor with two decades of industrial, construction and fire safety training experience. LBAU offers an economical HazCom GHS training course online. Custom training options for employers are available on location, or at the LBA University Training Center in Greenville, NC.

"The Dec. 1 GHS deadline is just the first in a series of rollouts of the new GHS standard by OSHA," said Dixon. "I would expect the agency to pay very close attention to compliance related issues as this new system is implemented."

Contact Bryan for a no obligation consultation about your professional safety training needs. He can help you determine if HazCom GHS training is needed and the best approached to achieve cost effective and efficient training. Contact Bryan at: bryan.dixon@lbagroup.com or 252-757-0279.

About LBA Group Inc.
LBA Group, Inc. has 50 years of experience in providing electromagnetic protection for industrial and telecommunications infrastructure assets. It is comprised of LBA University, Inc. providing on-site and online professional training; the professional engineering consultancy Lawrence Behr Associates, Inc.; and LBA Technology, Inc., a leading marketer and integrator of radio frequency systems, lightning protection, and EMC equipment for broadcast, industrial, and government users worldwide. The companies are based in Greenville, N.C., USA.

Keep up with the latest LBA news and industry information on Facebook at: www.facebook.com/LBAGroup.


David HornDavid Horn is an award-winning business and marketing development specialist with LBA Group, Inc. He helps some of the largest mobile carriers in the country implement regulatory compliance programs. LBA also utilizes his decades of experience in communications and new media to supplement the global marketing initiatives of the company. He specializes in turning complex topics into informative and entertaining stories.

 

The post Six Steps to Understanding HazCom GHS Compliance appeared first on LBA Blogs.

Monday, April 1, 2013

LBAU Introduces New GHS Online Training Course Hear No RF Evil - See No RF Evil

LBAU Introduces New GHS Online Training Course Hear No RF Evil - See No RF Evil

Link to LBA Blogs

LBAU Introduces New GHS Online Training Course

Posted: 01 Apr 2013 01:33 PM PDT

LBA University Launches Online OSHA HazCom GHS Training
Enables GHS training compliance by OSHA Dec. 1, 2013 deadline

Click here to view the press release.

Online OSHA HazCom GHS Training

The post LBAU Introduces New GHS Online Training Course appeared first on LBA Blogs.

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