Re: [ns] About wireless cards specifications simulation
Hi, Gabrial Monty schrieb: You have said that : To answer your question: NO, it is absolutely not realistic to deduce from a result of 150m transmission range to be in an indoor scenario. Do you mean that I cannot assume an indoor range to be 150m, or I cannot assume that an infrastructured network is working in an indoor environment? What I tried so say is: If your transmission range is 150m, you cannot assume to be in an indoor environment. For your question: a) you cannot assume that the transmission range will be 150m in an indoor environment. Usually, when someone gives a transmission range, he means that the transmission range can be _up to_ this value. You can never assume a minimum range (s. the elevator example). b) An infrastructured network is known to work in an indoor environment. The point that I want to get to, is that in the standard it is specified that the maximum transmit power for 802.11a cards in the range 5.725-5.825 GHz can reach 800 mW, following this can I assume a range of 150m (for example) for a card using 600 mW as its transmit power, apart from the propagation model or lets say I am working with TwoRayGround model, can I assume this or one can argue that my simulation settings are not real? In a general environment (one you have no specific knowledge about) you cannot assume anything (s. the elevator). If you define some properties of the environment as prerequisits (e.g. we are in an open park area with clear line-of-sight and no obstacles within the first fresnel zone) you can assume a transmission range with high confidence (e.g. 150m +/- 20m). In an indoor environment this is quite difficult because the variation is extremly high - something linke 50m +/- 50m does not help you much. Furthermore, even in a static indoor environment (one where anything remains at its position, no people moving, no doors opened/closed etc.) the signal strength between a pair of stationary WLAN transmitters will not be constant. You will find more information and references to other peoples' work in my thesis (http://deposit.ddb.de/cgi-bin/dokserv?idn=980478588) or in the papers of my collegues that continued / extended my work (http://wwwivs.cs.uni-magdeburg.de/EuK/forschung/publikationen/index.shtml). So my advise - start your work with a discussion of the properties of the environment, than that of your devices, and finally that of your protocol. From all this you can derive the performance of your communication / application with reasonable confidence. And don't forget - transmission power is a property of your devicey, but transmission range is not. It is a result of the combination of transmitter, receiver, environment, and signal encoding. Daniel. Daniel Mahrenholz [EMAIL PROTECTED] wrote: Hi, Gabrial Monty schrieb: I have to simulate an infrastructured wireless network behavior using different wireless cards specifications. I want to test the network performance using 802.11a cards with high transmit power level (not less than 600 mW). I have choosen the XtremeRange5 card but what I have realized is that its outdoor range is over 50 km and it indoor range is 150 m, during simulation if two nodes are further than 150 m the link throughput is 0, so is it realistic to assume that I deal with indoor networks? what I mean I am dealing with similar networks topology to wireless mesh networks, can I assume this network to be indoor and apply this NIC card specifications Basically there is no difference if you increase the transmission power or use a high gain antenna. So, apart from the transmission power, the sensitivity of the transceiver is what makes the most important difference between two wireless cards. Before you proceed with your work you should read something about wireless propagation. Just as an example, an outdoor range of 50km is only possible if the transmitter is placed high enough above ground. Otherwise you will not have a free line of sight and fresnel zone. When I remember right, for 50km distance the transmitter needs to be placed about 80m above ground. The environment defines how the transmitted signal is attenuated. Just imaging you are inside a metal elevator - then you probably get an indoor range of 1m. To answer your question: NO, it is absolutely not realistic to deduce from a result of 150m transmission range to be in an indoor scenario. I suggest that you start by selecting a propagation model that mimics the effects experienced in an indoor environment (e.g. multipath propagation, shadowing, interference ...). If you have such a propagation model, you can start to investigate effects caused by the transmission power, cars specification, protocol ... whatever you like. Hope that gets you started, Daniel. - Never miss a thing. Make Yahoo your homepage.
Re: [ns] About wireless cards specifications simulation
Hi, Gabrial Monty schrieb: I have to simulate an infrastructured wireless network behavior using different wireless cards specifications. I want to test the network performance using 802.11a cards with high transmit power level (not less than 600 mW). I have choosen the XtremeRange5 card but what I have realized is that its outdoor range is over 50 km and it indoor range is 150 m, during simulation if two nodes are further than 150 m the link throughput is 0, so is it realistic to assume that I deal with indoor networks? what I mean I am dealing with similar networks topology to wireless mesh networks, can I assume this network to be indoor and apply this NIC card specifications Basically there is no difference if you increase the transmission power or use a high gain antenna. So, apart from the transmission power, the sensitivity of the transceiver is what makes the most important difference between two wireless cards. Before you proceed with your work you should read something about wireless propagation. Just as an example, an outdoor range of 50km is only possible if the transmitter is placed high enough above ground. Otherwise you will not have a free line of sight and fresnel zone. When I remember right, for 50km distance the transmitter needs to be placed about 80m above ground. The environment defines how the transmitted signal is attenuated. Just imaging you are inside a metal elevator - then you probably get an indoor range of 1m. To answer your question: NO, it is absolutely not realistic to deduce from a result of 150m transmission range to be in an indoor scenario. I suggest that you start by selecting a propagation model that mimics the effects experienced in an indoor environment (e.g. multipath propagation, shadowing, interference ...). If you have such a propagation model, you can start to investigate effects caused by the transmission power, cars specification, protocol ... whatever you like. Hope that gets you started, Daniel.
Re: [ns] About wireless cards specifications simulation
Hi, First of all thanks alot for your fast response. You have said that : To answer your question: NO, it is absolutely not realistic to deduce from a result of 150m transmission range to be in an indoor scenario. Do you mean that I cannot assume an indoor range to be 150m, or I cannot assume that an infrastructured network is working in an indoor environment? The point that I want to get to, is that in the standard it is specified that the maximum transmit power for 802.11a cards in the range 5.725-5.825 GHz can reach 800 mW, following this can I assume a range of 150m (for example) for a card using 600 mW as its transmit power, apart from the propagation model or lets say I am working with TwoRayGround model, can I assume this or one can argue that my simulation settings are not real? Thanks again and waiting your reply, gaby Daniel Mahrenholz [EMAIL PROTECTED] wrote: Hi, Gabrial Monty schrieb: I have to simulate an infrastructured wireless network behavior using different wireless cards specifications. I want to test the network performance using 802.11a cards with high transmit power level (not less than 600 mW). I have choosen the XtremeRange5 card but what I have realized is that its outdoor range is over 50 km and it indoor range is 150 m, during simulation if two nodes are further than 150 m the link throughput is 0, so is it realistic to assume that I deal with indoor networks? what I mean I am dealing with similar networks topology to wireless mesh networks, can I assume this network to be indoor and apply this NIC card specifications Basically there is no difference if you increase the transmission power or use a high gain antenna. So, apart from the transmission power, the sensitivity of the transceiver is what makes the most important difference between two wireless cards. Before you proceed with your work you should read something about wireless propagation. Just as an example, an outdoor range of 50km is only possible if the transmitter is placed high enough above ground. Otherwise you will not have a free line of sight and fresnel zone. When I remember right, for 50km distance the transmitter needs to be placed about 80m above ground. The environment defines how the transmitted signal is attenuated. Just imaging you are inside a metal elevator - then you probably get an indoor range of 1m. To answer your question: NO, it is absolutely not realistic to deduce from a result of 150m transmission range to be in an indoor scenario. I suggest that you start by selecting a propagation model that mimics the effects experienced in an indoor environment (e.g. multipath propagation, shadowing, interference ...). If you have such a propagation model, you can start to investigate effects caused by the transmission power, cars specification, protocol ... whatever you like. Hope that gets you started, Daniel. - Never miss a thing. Make Yahoo your homepage.
