Wireless networks are based on the IEEE 802.11 standards. A basic wireless network consists of multiple stations communicating with radios that broadcast in either the 2.4GHz or 5GHz band (though this varies according to the locale and is also changing to enable communication in the 2.3Ghz and 4.9Ghz ranges).
802.11 networks are organized in two ways: in a BSS one station acts as a master with all the other stations associating to it; this is termed infrastructure mode and the master station is termed an access point (AP). In BSS mode all communication passes through the AP; even when one station wants to communicate with another wireless station messages must go through the AP. In the second form of network there is no master and stations communicate directly. This form of network is termed an IBSS and is commonly know as an adhoc network.
802.11 networks were first created in the 2.4GHz band using protocols defined by the IEEE 802.11b standard. These specifications include the operating frequencies, MAC layer characteristics including framing and transmission rates (communication can be done at various rates). Later the 802.11a standard defined operation in the 5GHz band, including different signalling mechanisms and higher transmission rates. Still later the 802.11g standard was defined to enable use of 802.11a signalling and transmission mechanisms in the 2.4GHz band in such a way as to be backwards compatible with 802.11b networks.
Separate from the underlying transmission techniques 802.11 networks have a variety of security mechanisms. The original 802.11 specifications defined a simple security protocol called WEP. This protocol uses a fixed pre-shared key and the RC4 cryptographic cipher to encode data transmitted on a network. Stations must all agree on the identity of the fixed key in order to communmicate. This scheme was shown to be easily broken and is now rarely used except to discourage transient users from joining networks. Current security practice is given by the IEEE 802.11i specification which defines new cryptographic ciphers and an additional protocol to authenticate stations to an access point and exchange keys for doing data communication. Further, cryptographic keys are periodically refreshed and there are mechanisms for detecting intrusion attempts (and for countering intrusion attempts). Another security protocol specification commonly used in wireless networks is termed WPA. This was a precursor to 802.11i defined by an industry group as an interim measure while waiting for 802.11i to be ratified. WPA specifies a subset of the requirements found in 802.11i and is designed for implementation on legacy hardware. Specifically WPA defines the TKIP protocol that is derived from the original WEP protocol. 802.11i permits use of TKIP but most stations will instead use the AES cipher for encrypting data; a cipher that is too computationally costly to be implemented on legacy hardware.
Other than the above protocol standards the other important standard to be aware of is 802.11e. This defines protocols for deploying multi-media applications such as streaming video and voice over IP (VoIP) in an 802.11 network. Like 802.11i, 802.11e also has a precursor specification termed WME (and now WMM) that has been defined by an industry group as a subset of 802.11e that can be implemented now to enable multi-media applications while waiting for the final ratification of 802.11e. The most important thing to understand about 802.11e and WME/WMM is that it enables prioritized traffic use of a wireless network through Quality of Service (QoS) protocols and enhanced media access protocols. Proper implementation of these protocols enable high speed bursting of data and prioritized traffic flow.
FreeBSD 6.0 supports networks that operate using 802.11a, 80.211b, and 802.11g. The WPA and 802.11i security protocols are likewise supported (in conjunction with any of 11a, 11b, and 11g) and QoS and traffic prioritization required by the WME/WMM protocols are supported for a limited set of wireless devices.
Thursday, December 18, 2008
Tuesday, December 16, 2008
Wireshark Wireless
Wireshark is a network packet analyzer. A network packet analyzer will try to capture network packets and tries to display that packet data as detailed as possible.
Wireshark's powerful features make it the tool of choice for network troubleshooting, protocol development, and education worldwide. Wireshark was written by an international group of networking experts, and is an example of the power of open source. It runs on Windows, Linux, UNIX, and other platforms.
In this Wireshark Tutorial we will look at how to decode wireless lan 802.11 packets and understand them using Wireshark. This will be particularly useful if you desire to write your own wireless lan monitoring , wireless lan management or wireless lan security product.
The Ethereal network protocol analyzer has changed its name to Wireshark.
The name might be new, but the software is the same. Wireshark's powerful features make it the tool of choice for network troubleshooting, protocol development, and education worldwide.
Wireshark was written by networking experts around the world, and is an example of the power of open source
Wireshark is used by network professionals around the world for analysis, troubleshooting, software and protocol development and education.
The program has all of the standard features you would expect in a protocol analyzer, and several features not seen in any other product. Its open source license allows talented experts in the networking community to add enhancements.
Wireshark's powerful features make it the tool of choice for network troubleshooting, protocol development, and education worldwide. Wireshark was written by an international group of networking experts, and is an example of the power of open source. It runs on Windows, Linux, UNIX, and other platforms.
In this Wireshark Tutorial we will look at how to decode wireless lan 802.11 packets and understand them using Wireshark. This will be particularly useful if you desire to write your own wireless lan monitoring , wireless lan management or wireless lan security product.
The Ethereal network protocol analyzer has changed its name to Wireshark.
The name might be new, but the software is the same. Wireshark's powerful features make it the tool of choice for network troubleshooting, protocol development, and education worldwide.
Wireshark was written by networking experts around the world, and is an example of the power of open source
Wireshark is used by network professionals around the world for analysis, troubleshooting, software and protocol development and education.
The program has all of the standard features you would expect in a protocol analyzer, and several features not seen in any other product. Its open source license allows talented experts in the networking community to add enhancements.
Sunday, December 14, 2008
EMC ANTENNAS FOR TESTING UP TO 40 GHz
Com-Power EMI / EMC broadband and tuned antennas cover the frequency range of 9 kHz - 40 GHz for EMI/EMCTesting. They can be used for both radiated emission and immunity testing (antenna used as a transmitter to generate electromagnetic field).These antenna were intended for use in an EMI/ EMC testing laboratory to test electronic products to certify that they meet the various international EMC regulatory standards. However, they are also suitable for troubleshooting EMI problems by the product manufacturer before going to test EMC.
Below is the list of antennas available from Com-Power. Most of the antennas listed below are available from stock. Please contact Com-Power or local representative for price availibility or use request quote link above.
EMI / EMC ANTENNAS
Biconical Antenna - Model AB-900
Frequency Range: 30 MHz-300 MHz
Polarization: Linear
Power handling: 50 Watts continuous
Impedance: Matched to 50 Ohm
Connector: BNC (f)
Weight: 7 lbs.
Size: (L x W) 28.75" x 52.75"
Log Perioidic Antenna - Model AL-100
Frequency Range: 300 MHz - 1000 MHz
Continuous Power (CW): 50 Watts
Polarization: Linear
Impedance: 50 Ohms
Connector: BNC Female
Width: 22 inches (at the widest Point) Length: 37 inches
Weight: 4 lbs.
Half Wave Tuned Dipole Antenna Set- Model AD-100
Frequency Ranges:
Balun 1 : 30 MHz - 65 MHz
Balun 2 : 65 MHz - 175 MHz
Balun 3 : 175 MHz - 400 MHz
Balun 4 : 400 MHz - 1000 MHz
Impedance: 50 Ohm
Connector Type: BNC female
Element length assembled: min: 6 inches, max: 212 inches
Weight: 8 lbs,
Carrying case included (not shown)
Combilog Antenna- Model AC-213 & AC-220
Frequency Range:
30 MHz - 2000 MHz (AC-220)
30 MHz - 1300 MHz (AC-213)
Power handling: 500 Watts
Gain: 5 dBi min. (200 MHz -2000 MHz)
Impedance: matched to 50 Ohm
Connector: Type N Female
VSWR: 2:1 ( 80 MHz - 2000 MHz)
Weight: 8 lbs.
Dimensions ((L x W x H): 38 x 50 x 25 inches
Log Periodic antenna - Model ALP-100
Frequency Range:
300 MHz - 1000 MHz
Power handling: 500 Watts
Impedance: matched to 50 Ohm
Connector: Type N Female
VSWR: 2:1
Weight: 4 lbs.
Dimensions ((L x W x H): 19 x 21 x 2.5 inches
Double Ridged Horn Antenna- Model AH-118
Frequency Range: 1 GHz - 18 GHz
Input Power (CW): 300 Watts
VSWR: 2.0 : 1
Polorization: Linear
Impedance: 50 Ohm
Connector type: N Female
Weight: 4 lb.
Size: 7.8" X 9.5" X 5.6" max.
Double Ridged Horn Antenna- Model AH-220
Frequency Range: 200 MHz - 2000 MHz
Input: 500 Watt CW
Antenna VSWR (average): 2.5 :1
Polarization: Linear
Output Impedance: 50 Ohm
Connector types
Antenna output: N (f)
Weight: 27 lbs.
Size: 37 " X 38 " X 27 "
Active Double Ridged Horn Antenna- Model AHA-118
Frequency Range: 1 GHz - 18 GHz
Built in Preamplifier: 25 dB Gain
Antenna VSWR: 2.0 :1
Polarization: Linear
Output Impedance: 50 Ohm
Connector types
Antenna output: N (f)
Preamplifier input: N (f)
Preamplifier output: N (f)
Power input: 18 VDC, 500 mA
Weight: 7 lbs.
Size: 10.2" X 9.5" X 5.6"
Horn Antennas 18 - 40 GHz
Model AH-826
Frequency Range: 18 GHz - 26.5 GHz
Power handling (CW): 5 Watts
VSWR: 2.0 :1
Polorization: Linear
Connector type: K type (will mate with SMA)
Impedance: 50 Ohms
Weight: 1.5 lbs.
Size (L x W x H): 8.7 x 5.7 x 12 inches max.Model AH-640
Frequency Range: 26.5 GHz - 40 GHz
Power handling: 5 Watts CW
VSWR: 2.0 :1.0
Polarization: Linear
Connector type: K type (will mate with SMA)
Impedance: 50 Ohms
Weight: 1.5 lbs.
Size (L x W x H): 8.7 x 5.7 x 9 inches max.Model AH-840
Frequency Range: 18 GHz - 40 GHz
Power handling: 5 Watts CW
VSWR: 2.0 :1.0
Connector type: K type female
Polarization: Linear
Impedance: 50 Ohms
Weight: 2 lbs. max. (0.9 kg)
Size (L xW xH): 8.7 x 2.7 x 7.5" inches
Active Loop Antenna- Model AL-130
Frequency range: 9 kHz - 30 MHz
Dynamic range: 110 dB at 1 MHz
Sensitivity: 10 dBµV/m at 1 MHz
Electric antenna factor: 13 dB at 1 MHz
1 dB compression point: 3 V/m
Output Impedance: 50 Ohm
Connector type: BNC
Power: 2 ea. 6V rechargable sealed lead-acid
battery cells
Weight: 4 lbs.
Loop diameter: 19 inches
Dimensions: 9" x 5" x 7" max.(Amplifier Housing)
Active 41 inch Monopole antenna- Model AM-741
Frequency Range: 9 kHz - 30 MHz
Output Impedance: 50 Ohm
Connector Type: BNC (f) input and Output
Collapsible Element Length: 41 inches (fully extended)
Base Plate (counterpoise): 24 x 24 inches
Battery Type: 6 V NimH
Charger input: 6 VDC, 500 mA.
Weight:15 lb.
Friday, December 12, 2008
WIRELESS DATA SOLUTIONS
This community’s objective is to leverage its existing wireless knowledge to become the premier worldwide source of wireless data application information. We are committed to crafting solutions that best meet your mobile data needs. Mobitex Professionals are experts at identifying end-user applications, hardware, and wireless service into two-way wireless data solutions that provide you with a competitive advantage.
Business knowledge and technical expertise are the keys to wireless business solutions. A wireless business solution is a set of components designed to meet your mobile data needs. Selecting the best components requires expertise in understanding how each relative component affects the overall solution. We have knowledge of each specific market for wireless data solutions over a varied application and coverage environment.
This web site was developed to provide answers of how MOBITEX "fits" in today's ever changing wireless landscape. There are multiple machine-to-machine, people to machine, and people to people applications that are ideally suited for Mobitex Technology.
Business knowledge and technical expertise are the keys to wireless business solutions. A wireless business solution is a set of components designed to meet your mobile data needs. Selecting the best components requires expertise in understanding how each relative component affects the overall solution. We have knowledge of each specific market for wireless data solutions over a varied application and coverage environment.
This web site was developed to provide answers of how MOBITEX "fits" in today's ever changing wireless landscape. There are multiple machine-to-machine, people to machine, and people to people applications that are ideally suited for Mobitex Technology.
Thursday, December 11, 2008
Optical Wireless Sensor
We analyze an optical wireless sensor network system that uses corner cube retroreflectors (CCRs). A CCR consists of three flat mirrors in a concave configuration. When a light beam enters the CCR, it bounces off each of the three mirrors, and is reflected back parallel to the direction it entered. A CCR can send information to the base station by modulating the reflected beam by vibrating the CCR or interrupting the light path; the most suitable transmission format is on-off keying (OOK). The CCR is attractive in many optical communication applications because it is small, easy to operate, and has low power consumption. This paper examines two signal decision schemes for use at the base station: collective decision and majority decision. In collective decision, all optical signals detected by the sensors are received by one photodetector (PD), and its output is subjected to hard decision. In majority decision, the outputs of the PDs associated with the sensors are subjected to hard detection, and the final data is decided by majority decision. We show that increasing the number of sensors improves the bit error rate (BER). We also show that when the transmitted optical power is sufficiently large, BER depends on sensor accuracy. We confirm that collective decision yields lower BERs than majority decision.
Wireless Sensor Network
A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations. The development of wireless sensor networks was originally motivated by military applications such as battlefield surveillance. However, wireless sensor networks are now used in many civilian application areas, including environment and habitat monitoring, healthcare applications, home automation, and traffic control.
In addition to one or more sensors, each node in a sensor network is typically equipped with a radio transceiver or other wireless communications device, a small microcontroller, and an energy source, usually a battery. The envisaged size of a single sensor node can vary from shoebox-sized nodes down to devices the size of grain of dust, although functioning 'motes' of genuine microscopic dimensions have yet to be created. The cost of sensor nodes is similarly variable, ranging from hundreds of dollars to a few cents, depending on the size of the sensor network and the complexity required of individual sensor nodes. Size and cost constraints on sensor nodes result in corresponding constraints on resources such as energy, memory, computational speed and bandwidth.
A sensor network normally constitutes a wireless ad-hoc network, meaning that each sensor supports a multi-hop routing algorithm (several nodes may forward data packets to the base station).
In computer science and telecommunications, wireless sensor networks are an active research area with numerous workshops and conferences arranged each year.
In addition to one or more sensors, each node in a sensor network is typically equipped with a radio transceiver or other wireless communications device, a small microcontroller, and an energy source, usually a battery. The envisaged size of a single sensor node can vary from shoebox-sized nodes down to devices the size of grain of dust, although functioning 'motes' of genuine microscopic dimensions have yet to be created. The cost of sensor nodes is similarly variable, ranging from hundreds of dollars to a few cents, depending on the size of the sensor network and the complexity required of individual sensor nodes. Size and cost constraints on sensor nodes result in corresponding constraints on resources such as energy, memory, computational speed and bandwidth.
A sensor network normally constitutes a wireless ad-hoc network, meaning that each sensor supports a multi-hop routing algorithm (several nodes may forward data packets to the base station).
In computer science and telecommunications, wireless sensor networks are an active research area with numerous workshops and conferences arranged each year.
Optical Wireless
Optical wireless refers to the combined use of two technologies - conventional radio-frequency (RF) wireless and optical fiber - for telecommunication. Long-range links are provided by optical fiber (also known as fiber optic cables), and links from the long-range end-points to end users are accomplished by RF wireless. Sometimes the local links are provided by laser systems, also known as free-space optics (FSO), rather than by RF wireless.
A major problem facing the developers of fiber optic communications systems is the fact that it is expensive to provide each end user with a separate fiber optic line. While this has been done for large corporations in a few geographic regions, the fiber-to-the-home ideal remains impractical. But RF wireless at ultra-high frequencies (UHF) and microwave frequencies can carry broadband signals to individual computers at substantial data speeds, and the cost is reasonable.
A typical optical wireless system would bring fiber optics into a town, where one or more hubs are set up with transponders that convert optical signals to and from RF wireless signals. It would be easy to add new subcribers to any hub by means of multiplexing. Subscribers would be equipped with individual RF wireless modems, and able to move around anywhere within the zone of coverage, making portable, as well as fixed system, operation, practical.
Optimistic engineers predict that, with the deployment of optical wireless on a large scale, data speeds of 100 gigabits per second (100 Gbps) will someday be enjoyed by many small companies and home subscribers.
A major problem facing the developers of fiber optic communications systems is the fact that it is expensive to provide each end user with a separate fiber optic line. While this has been done for large corporations in a few geographic regions, the fiber-to-the-home ideal remains impractical. But RF wireless at ultra-high frequencies (UHF) and microwave frequencies can carry broadband signals to individual computers at substantial data speeds, and the cost is reasonable.
A typical optical wireless system would bring fiber optics into a town, where one or more hubs are set up with transponders that convert optical signals to and from RF wireless signals. It would be easy to add new subcribers to any hub by means of multiplexing. Subscribers would be equipped with individual RF wireless modems, and able to move around anywhere within the zone of coverage, making portable, as well as fixed system, operation, practical.
Optimistic engineers predict that, with the deployment of optical wireless on a large scale, data speeds of 100 gigabits per second (100 Gbps) will someday be enjoyed by many small companies and home subscribers.
Wednesday, December 10, 2008
Wireless WAN Solutions
Extend your network infrastructure with long range
outdoor wireless Ethernet connections
Trango's long range fixed wireless broadband Ethernet equipment is ideal for all types of wireless wide area network (WWAN) and wireless local area network (WLAN) applications. Trango outdoor wireless networking solutions allow you to quickly, easily, and cost effectively deploy reliable, high-speed, secure wireless IP connections between multiple remote locations at distances up to 45+ miles, and enable you to eliminate your costly leased lines and avoid expensive time consuming fiber trenching.
Wireless WAN Applications
Wireless WAN applications are endless for Trango long-range wireless Ethernet bridges. For example, a business may need to link its IT infrastructure to a few outlying buildings; a university or any school may need to provide internet access to dormitories or other buildings across campus; or a hospital may need to establish a secure link to a clinic across town so that doctors may securely exchange patient information over a high-speed connection.
Whether you need to a network connection across the street, across town, or from urban to rural areas, Trango wireless WAN/LAN building-to-building outdoor networks are ideal for any private enterprise or network operator that requires high-speed connectivity between two or more remote locations. Trango long range wireless wide area network (WWAN) solutions are well suited for a wide variety of industries and applications because they deliver high-capacity bandwidth, are extremely reliable, highly secure, and can be established with minimal effort and cost.
Licensed Point-to-Point Wireless WAN Radios
* TrangoLINK Giga® is a split-architecture (ODU/IDU) full duplex RF microwave system link that is both native Ethernet and native-TDM.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
outdoor wireless Ethernet connections
Trango's long range fixed wireless broadband Ethernet equipment is ideal for all types of wireless wide area network (WWAN) and wireless local area network (WLAN) applications. Trango outdoor wireless networking solutions allow you to quickly, easily, and cost effectively deploy reliable, high-speed, secure wireless IP connections between multiple remote locations at distances up to 45+ miles, and enable you to eliminate your costly leased lines and avoid expensive time consuming fiber trenching.
Wireless WAN Applications
Wireless WAN applications are endless for Trango long-range wireless Ethernet bridges. For example, a business may need to link its IT infrastructure to a few outlying buildings; a university or any school may need to provide internet access to dormitories or other buildings across campus; or a hospital may need to establish a secure link to a clinic across town so that doctors may securely exchange patient information over a high-speed connection.
Whether you need to a network connection across the street, across town, or from urban to rural areas, Trango wireless WAN/LAN building-to-building outdoor networks are ideal for any private enterprise or network operator that requires high-speed connectivity between two or more remote locations. Trango long range wireless wide area network (WWAN) solutions are well suited for a wide variety of industries and applications because they deliver high-capacity bandwidth, are extremely reliable, highly secure, and can be established with minimal effort and cost.
Licensed Point-to-Point Wireless WAN Radios
* TrangoLINK Giga® is a split-architecture (ODU/IDU) full duplex RF microwave system link that is both native Ethernet and native-TDM.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
wireless rf wlan solutions
* TrangoLINK Giga® is a split-architecture (ODU/IDU) full duplex RF microwave system link that is both native Ethernet and native-TDM.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
* TrangoLINK® Apex is an all-outdoor full duplex RF microwave radio that is native-Ethernet for 100% IP traffic.
* ATLAS 4900™ is an all-outdoor native Ethernet OFDM 4.9 GHz wireless bridge that operates in the licensed Public Safety band.
Unlicensed Point-to-Point Wireless WAN Radios
* TrangoLINK-45™ is an all-outdoor, native Ethernet, multi-band OFDM wireless Ethernet bridge that is capable of operation in 4 different 5 GHz bands (5.2, 5.3, 5.4, 5.8 GHz).
* TrangoLINK-10™ is an all-outdoor, native Ethernet 5.8 GHz wireless bridge.
Unlicensed Point-to-MultiPoint Wireless WAN Radios
For delivering point-to-multipoint (PtMP) broadband access wireless WAN connectivity from a central office to many remote offices, Trango offers these robust solutions.
* Access5830™ System 5.8 GHz broadband wireless access system delivers up to 10 Mbps up to 18 miles.
* Trango M2400S™ 2.4 GHz broadband wireless access system delivers up to 5 Mbps up to 25 miles.
* Trango M900S™ 900 MHz broadband wireless access system delivers up to 3 Mbps up to 20 miles.
Wireless Amplifier
In November 2006, Marin Soljačić and other researchers at the Massachusetts Institute of Technology applied the near field behaviour well known in electromagnetic theory to a wireless power transmission concept based on strongly-coupled resonators.[12][13][14] In a theoretical analysis (see Ref: Annals of Physics), they demonstrate that, by designing electromagnetic resonators that suffer minimal loss due to radiation and absorption and have a near field with mid-range extent (namely a few times the resonator size), mid-range efficient wireless energy-transfer is possible. The reasonment is that, if two such resonant objects are brought in mid-range proximity, their near fields (consisting of so-called 'evanescent waves') couple (evanescent wave coupling) and can allow the energy to tunnel/transfer from one object to the other within times much shorter than all loss times, which were designed to be long, and thus with the maximum possible energy-transfer efficiency. Since the resonant wavelength is much larger than the resonators, the field can circumvent extraneous objects in the vicinity and thus this mid-range energy-transfer scheme does not require line-of-sight. By utilizing in particular the magnetic field to achieve the coupling, this method can be safe, since magnetic fields interact weakly with living organisms.
On June 7, 2007, it was reported that a prototype system had been implemented.[10][11] In an experimental demonstration (see Ref: Science), the MIT researchers successfully demonstrated the ability to power a 60-watt light bulb wirelessly using two copper coils of 60cm diameter that were 2m (7ft) away at roughly 45% efficiency. The coils were designed to resonate together at 10MHz and were oriented along the same axis. One was connected inductively to a power source, and the other one to a bulb. The setup powered the bulb on, even when the direct line of sight was blocked using a wooden panel.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
Beginning in the early 1960s resonant inductive wireless energy transfer was used successfully in implantable medical devices [15] including such devices as pacemakers and artificial hearts. While the early systems used a resonant receiver coil later systems [16] implemented resonant transmitter coils as well. These medical devices are designed for high efficiency using low power electronics while efficiently accommodating some misalignment and dynamic twisting of the coils. The separation between the coils in implantable applications is commonly less than 20 cm. Today resonant inductive energy transfer is regularly used for providing electric power in many commercially available medical implantable devices.[17]
Wireless electric energy transfer for experimentally powering electric automobiles and buses is a higher power application (>10kW) of resonant inductive energy transfer. High power levels are required for rapid recharging and high energy transfer efficiency is required both for operational economy and to avoid negative environmental impact of the system. An experimental electrified roadway test track built circa 1990 achieved 80% energy efficiency while recharging the battery of a prototype bus at a specially equipped bus stop [18] [19]. The bus could be outfitted with a retractable receiving coil for greater coil clearance when moving. The gap between the transmit and receive coils was designed to be less than 10 cm when powered. In addition to buses the use of wireless transfer has been investigated for recharging electric automobiles in parking spots and garages as well.
Some of these wireless resonant inductive devices operate at low milliwatt power levels and are battery powered. Others operate at higher kilowatt power levels. Current implantable medical and road electrification device designs achieve more than 75% transfer efficiency at an operating distance between the transmit and receive coils of less than 10 cm.
On June 7, 2007, it was reported that a prototype system had been implemented.[10][11] In an experimental demonstration (see Ref: Science), the MIT researchers successfully demonstrated the ability to power a 60-watt light bulb wirelessly using two copper coils of 60cm diameter that were 2m (7ft) away at roughly 45% efficiency. The coils were designed to resonate together at 10MHz and were oriented along the same axis. One was connected inductively to a power source, and the other one to a bulb. The setup powered the bulb on, even when the direct line of sight was blocked using a wooden panel.
"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
Beginning in the early 1960s resonant inductive wireless energy transfer was used successfully in implantable medical devices [15] including such devices as pacemakers and artificial hearts. While the early systems used a resonant receiver coil later systems [16] implemented resonant transmitter coils as well. These medical devices are designed for high efficiency using low power electronics while efficiently accommodating some misalignment and dynamic twisting of the coils. The separation between the coils in implantable applications is commonly less than 20 cm. Today resonant inductive energy transfer is regularly used for providing electric power in many commercially available medical implantable devices.[17]
Wireless electric energy transfer for experimentally powering electric automobiles and buses is a higher power application (>10kW) of resonant inductive energy transfer. High power levels are required for rapid recharging and high energy transfer efficiency is required both for operational economy and to avoid negative environmental impact of the system. An experimental electrified roadway test track built circa 1990 achieved 80% energy efficiency while recharging the battery of a prototype bus at a specially equipped bus stop [18] [19]. The bus could be outfitted with a retractable receiving coil for greater coil clearance when moving. The gap between the transmit and receive coils was designed to be less than 10 cm when powered. In addition to buses the use of wireless transfer has been investigated for recharging electric automobiles in parking spots and garages as well.
Some of these wireless resonant inductive devices operate at low milliwatt power levels and are battery powered. Others operate at higher kilowatt power levels. Current implantable medical and road electrification device designs achieve more than 75% transfer efficiency at an operating distance between the transmit and receive coils of less than 10 cm.
Wireless Support
At this moment only the RT25USB-SRC-V2.0.7.0 driver from Ralink is succesfully ported and reported to be working with an ASUS WL-167G USB dongle on 2.6.5-it0. This tutorial gives enough information to easily use the ASUS WL-167G on your OSD, but also gives enough information for everyone who wants to port another driver.
So what do you need:
* kernel 2.6.5-it0 with wireless extensions enabled, this is due to the broken USB Host driver in 2.6.15 (instructions below)
* dongle with RT2570 chipset, see serialmonkey for a list
* the source code of the dongle driver. I've succesfully 'ported' the RT25USB-SRC-V2.0.7.0 driver from Ralink
* and some version of wireless tools to send commands to the dongle, available here
* wireless support has only been tested with the developer OSD (green PCB). If you have the yellow/orange one shipped from thinkgeek then you could be the first to get wireless working on a BETA sample!
The broken USB Host driver is expected to be fixed by the manufacturer around 9/12. Until this time you will have to downgrade your OSD to a 2.6.5 kernel... and probably has the consequence that you can't play any video/audio
So what do you need:
* kernel 2.6.5-it0 with wireless extensions enabled, this is due to the broken USB Host driver in 2.6.15 (instructions below)
* dongle with RT2570 chipset, see serialmonkey for a list
* the source code of the dongle driver. I've succesfully 'ported' the RT25USB-SRC-V2.0.7.0 driver from Ralink
* and some version of wireless tools to send commands to the dongle, available here
* wireless support has only been tested with the developer OSD (green PCB). If you have the yellow/orange one shipped from thinkgeek then you could be the first to get wireless working on a BETA sample!
The broken USB Host driver is expected to be fixed by the manufacturer around 9/12. Until this time you will have to downgrade your OSD to a 2.6.5 kernel... and probably has the consequence that you can't play any video/audio
Wireless 3G DR RF Solutions
Wirelss Wide Area Network A WWAN differs from a WLAN (wireless LAN) in that it uses Mobile telecommunication cellular network technologies such as WIMAX (though it's better applicated into WMAN Networks), UMTS, GPRS, CDMA2000, GSM, CDPD, Mobitex, HSDPA or 3G to transfer data. It can use also LMDS and Wi-Fi to connect to the Internet. These cellular technologies are offered regionally, nationwide, or even globally and are provided by a wireless service provider for a monthly usage fee.[1] WWAN connectivity allows a user with a laptop and a WWAN card to surf the web, check email, or connect to a Virtual Private Network (VPN) from anywhere within the regional boundaries of cellular service. Various computers now have integrated WWAN capabilities (Such as HSDPA in Centrino). This means that the system has a cellular radio (GSM/CDMA) built in, which allows the user to send and receive data. There are two basic means that a mobile network may use to transfer data:
Packet-switched Data Networks (GPRS/CDPD)
Circuit-switched dial-up connections
Since radio communications systems do not provide a physically secure connection path, WWANs typically incorporate encryption and authentication methods to make them more secure. Unfortunately some of the early GSM encryption techniques were flawed, and security experts have issued warnings that cellular communication, including WWANs, is no longer secure.[2] UMTS(3G) encryption was developed later and has yet to be broken.
Examples of providers for WWAN include Sprint Nextel, Verizon, and AT&T.
Packet-switched Data Networks (GPRS/CDPD)
Circuit-switched dial-up connections
Since radio communications systems do not provide a physically secure connection path, WWANs typically incorporate encryption and authentication methods to make them more secure. Unfortunately some of the early GSM encryption techniques were flawed, and security experts have issued warnings that cellular communication, including WWANs, is no longer secure.[2] UMTS(3G) encryption was developed later and has yet to be broken.
Examples of providers for WWAN include Sprint Nextel, Verizon, and AT&T.
LAN - Local Area Network
Definition: A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. A LAN is useful for sharing resources like files, printers, games or other applications. A LAN in turn often connects to other LANs, and to the Internet or other WAN.
Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist.
Specialized operating system software may be used to configure a local area network. For example, most flavors of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources.
The term LAN party refers to a multiplayer gaming event where participants bring their own computers and build a temporary LAN.
Also Known As: local area network
Examples: The most common type of local area network is an Ethernet LAN. The smallest home LAN can have exactly two computers; a large LAN can accommodate many thousands of computers. Many LANs are divided into logical groups called subnets. An Internet Protocol (IP) "Class A" LAN can in theory accommodate more than 16 million devices organized into subnets.
Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist.
Specialized operating system software may be used to configure a local area network. For example, most flavors of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources.
The term LAN party refers to a multiplayer gaming event where participants bring their own computers and build a temporary LAN.
Also Known As: local area network
Examples: The most common type of local area network is an Ethernet LAN. The smallest home LAN can have exactly two computers; a large LAN can accommodate many thousands of computers. Many LANs are divided into logical groups called subnets. An Internet Protocol (IP) "Class A" LAN can in theory accommodate more than 16 million devices organized into subnets.
Wireless LAN
A wireless LAN or WLAN or wireless local area network is the linking of two or more computers or devices using spread-spectrum or OFDM modulation technology based to enable communication between devices in a limited area. This gives users the mobility to move around within a broad coverage area and still be connected to the network.
For the home user, wireless has become popular due to ease of installation, and location freedom with the gaining popularity of laptops. Public businesses such as coffee shops or malls have begun to offer wireless access to their customers; some are even provided as a free service. Large wireless network projects are being put up in many major cities. Google is even providing a free service to Mountain View, California[1] and has entered a bid to do the same for San Francisco.[2] New York City has also begun a pilot program to cover all five boroughs of the city with wireless Internet access
For the home user, wireless has become popular due to ease of installation, and location freedom with the gaining popularity of laptops. Public businesses such as coffee shops or malls have begun to offer wireless access to their customers; some are even provided as a free service. Large wireless network projects are being put up in many major cities. Google is even providing a free service to Mountain View, California[1] and has entered a bid to do the same for San Francisco.[2] New York City has also begun a pilot program to cover all five boroughs of the city with wireless Internet access
Wirelss Wide Area Network
Wirelss Wide Area Network A WWAN differs from a WLAN (wireless LAN) in that it uses Mobile telecommunication cellular network technologies such as WIMAX (though it's better applicated into WMAN Networks), UMTS, GPRS, CDMA2000, GSM, CDPD, Mobitex, HSDPA or 3G to transfer data. It can use also LMDS and Wi-Fi to connect to the Internet. These cellular technologies are offered regionally, nationwide, or even globally and are provided by a wireless service provider for a monthly usage fee.[1] WWAN connectivity allows a user with a laptop and a WWAN card to surf the web, check email, or connect to a Virtual Private Network (VPN) from anywhere within the regional boundaries of cellular service. Various computers now have integrated WWAN capabilities (Such as HSDPA in Centrino). This means that the system has a cellular radio (GSM/CDMA) built in, which allows the user to send and receive data. There are two basic means that a mobile network may use to transfer data:
Packet-switched Data Networks (GPRS/CDPD)
Circuit-switched dial-up connections
Since radio communications systems do not provide a physically secure connection path, WWANs typically incorporate encryption and authentication methods to make them more secure. Unfortunately some of the early GSM encryption techniques were flawed, and security experts have issued warnings that cellular communication, including WWANs, is no longer secure.[2] UMTS(3G) encryption was developed later and has yet to be broken.
Examples of providers for WWAN include Sprint Nextel, Verizon, and AT&T.
Packet-switched Data Networks (GPRS/CDPD)
Circuit-switched dial-up connections
Since radio communications systems do not provide a physically secure connection path, WWANs typically incorporate encryption and authentication methods to make them more secure. Unfortunately some of the early GSM encryption techniques were flawed, and security experts have issued warnings that cellular communication, including WWANs, is no longer secure.[2] UMTS(3G) encryption was developed later and has yet to be broken.
Examples of providers for WWAN include Sprint Nextel, Verizon, and AT&T.
Wireless Optical Mesh Solution Networks
ClearMesh Networks Wednesday launched a wireless optical mesh solution designed to fill the gap between copper, RF and fiber in delivering 5mbps to 100mbps services to small and midsized businesses.
“There isn’t a cost-effective way for carriers today to extend fiber to SMBs,” said Fima Vaisman, ClearMesh’s senior vice president of marketing, explaining their monthly spend of $500 to $1,000 does not support a fiber trench where it is not already available. “What we provide is a solution that extends the fiber core without having to trench fiber.”
It also provides higher bandwidth than do copper and RF solutions, such as Wi-Fi and WiMAX, he said. “If a customer needs more bandwidth and they are looking for an SLA, we think there is a gap between those solutions provided at the entry level by WiMAX and Wi-Fi, and the high-end level by fiber. There is a gap in the middle. That is the gap we are trying to serve.”
Available immediately, the ClearMesh Metro Grid solution includes the ClearMesh 300 node, which can be mounted on a pole or rooftop, and the ClearMesh Management System, which provides tools for installation, diagnostics, service analysis and provisioning. The ClearMesh 300 node combines wireless and optical technologies with a Layer 2 mesh architecture to deliver business-grade Ethernet.
“The ClearMesh 300 Node is a switching platform,” explained Vaisman. “It has an Ethernet switch with 2-gigabit Ethernet capacity. Four of the Ethernet ports are copper and they are connected to optical transceivers.”
The optical transceivers, he said, are LED-based, which gives them a wider beam than systems using lasers, like free-space optics. “What that allows the product to do is be installed on a light pole as well as on top of a building,” said Vaisman. “A laser product cannot be installed on a light pole because the light pole has too much vibration, too much movement. The product wouldn’t stay locked on. With the product we have the light beams are locked on and stay locked on using automatic tracking whether on a light pole or building. With that you have a much broader ability to deploy a mesh in a metro area. If the device moves, the light cone still hits the other node.”
Each node has three optical transceivers, which operate on the license-free 850nm light band and reach 250 meters. Each transceiver is motorized, so it can move independently up and down, and 360 degrees around. “This allows each node to see three other nodes. Using that, we create a mesh,” said Vaisman, explaining the mesh requires one node to be fiber-feed, and several nodes can be fed from the same fiber to increase the capacity delivered into the mesh.
The ClearMesh node lists for $6,000, and less in volume. Considering installation costs, the company uses $5,000 per node in its ROI calculations. In contrast to trenching fiber, ClearMesh can cover seven buldings in a MetroGrid network for $35,000 in a matter of days while the fiber deployment over the same area will cost $180,000 and take months to install, he said. With a single customer per building and a single T1 replacement at $500 per month, the payback is 10 months, Vaisman said, adding a more realistic scenario is three customers per building paying $750 per month for a 10mbps service for an ROI of two months.
Yankee Group Analyst Tara Howard agrees that the ClearMesh solution serves “as a logical extension of a fiber network,” but she questions the market potential, discounting its appeal to Tier 1 companies that are laying fiber. “The opportunity is going to be with local LECs and municipalities,” she said, adding the fact that it does not compete with Wi-Fi or WiMAX is a plus.
“We don’t do what Wi-Fi does; we don’t offer mobility,” said Vaisman. “We don’t do what WiMAX does; we don’t offer five-mile reach. In a dense metro area, we offer high bandwidth and the ability to sign SLAs without any interference,” he said. The systems offers latency at one-tenth of 1ms, so 10 nodes equals 1ms of delay.
“There isn’t a cost-effective way for carriers today to extend fiber to SMBs,” said Fima Vaisman, ClearMesh’s senior vice president of marketing, explaining their monthly spend of $500 to $1,000 does not support a fiber trench where it is not already available. “What we provide is a solution that extends the fiber core without having to trench fiber.”
It also provides higher bandwidth than do copper and RF solutions, such as Wi-Fi and WiMAX, he said. “If a customer needs more bandwidth and they are looking for an SLA, we think there is a gap between those solutions provided at the entry level by WiMAX and Wi-Fi, and the high-end level by fiber. There is a gap in the middle. That is the gap we are trying to serve.”
Available immediately, the ClearMesh Metro Grid solution includes the ClearMesh 300 node, which can be mounted on a pole or rooftop, and the ClearMesh Management System, which provides tools for installation, diagnostics, service analysis and provisioning. The ClearMesh 300 node combines wireless and optical technologies with a Layer 2 mesh architecture to deliver business-grade Ethernet.
“The ClearMesh 300 Node is a switching platform,” explained Vaisman. “It has an Ethernet switch with 2-gigabit Ethernet capacity. Four of the Ethernet ports are copper and they are connected to optical transceivers.”
The optical transceivers, he said, are LED-based, which gives them a wider beam than systems using lasers, like free-space optics. “What that allows the product to do is be installed on a light pole as well as on top of a building,” said Vaisman. “A laser product cannot be installed on a light pole because the light pole has too much vibration, too much movement. The product wouldn’t stay locked on. With the product we have the light beams are locked on and stay locked on using automatic tracking whether on a light pole or building. With that you have a much broader ability to deploy a mesh in a metro area. If the device moves, the light cone still hits the other node.”
Each node has three optical transceivers, which operate on the license-free 850nm light band and reach 250 meters. Each transceiver is motorized, so it can move independently up and down, and 360 degrees around. “This allows each node to see three other nodes. Using that, we create a mesh,” said Vaisman, explaining the mesh requires one node to be fiber-feed, and several nodes can be fed from the same fiber to increase the capacity delivered into the mesh.
The ClearMesh node lists for $6,000, and less in volume. Considering installation costs, the company uses $5,000 per node in its ROI calculations. In contrast to trenching fiber, ClearMesh can cover seven buldings in a MetroGrid network for $35,000 in a matter of days while the fiber deployment over the same area will cost $180,000 and take months to install, he said. With a single customer per building and a single T1 replacement at $500 per month, the payback is 10 months, Vaisman said, adding a more realistic scenario is three customers per building paying $750 per month for a 10mbps service for an ROI of two months.
Yankee Group Analyst Tara Howard agrees that the ClearMesh solution serves “as a logical extension of a fiber network,” but she questions the market potential, discounting its appeal to Tier 1 companies that are laying fiber. “The opportunity is going to be with local LECs and municipalities,” she said, adding the fact that it does not compete with Wi-Fi or WiMAX is a plus.
“We don’t do what Wi-Fi does; we don’t offer mobility,” said Vaisman. “We don’t do what WiMAX does; we don’t offer five-mile reach. In a dense metro area, we offer high bandwidth and the ability to sign SLAs without any interference,” he said. The systems offers latency at one-tenth of 1ms, so 10 nodes equals 1ms of delay.
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