Re: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1
Charles, WOW! Great Post! That covers about everything. It increases the understanding of the complexity, but it doesn't answer the ultimate question, What to use. What we really want is an efficient OFDM system, with a strong TDD w/ARQ MAC, RFThreshold, Good Noise Filtering, Packet aggregating/compressing, adeqaute CPU processing, Quality narrow beam diversity antennas, all pre-packaged in a system/box under $300. But that product does not exist today. So why doesn't a manufacturer just make it, so we can stop debating what is best, and just deploy radios! Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Charles Wu [EMAIL PROTECTED] To: 'WISPA General List' wireless@wispa.org Sent: Thursday, December 28, 2006 4:47 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1 I go to see Mickey Mouse for a few days and look where this thread has gone...wow So, my 2 cents... One of the largest concerns in the license-exempt world is the question of a system's interference robustness. However, before we can get into further detail on the pros and cons of Alvarion VL vs Canopy, CSMA/CA vs GPS, etc -- it is necessary to realize that interference as a term is extremely broad and vague, and can mean just about anything to anyone. Heck, all radios in the market have some sort of interference robustness / avoidance capability -- the trick to understanding a system's capabilities is knowing what TYPE of interference the system can actually handle. Read on...I'll talk more about each particular platform when I get some time to write Part 2 =) WHAT IS INTERERENCE? In the wireless world, interference, by definition, is a situation where unwanted radio signals operate in the same frequency channels or bands - i.e. they mutually interfere, disrupt or add to the overall noise level in the intended transmission. Interference can be divided into two forms, based on whether it comes from your own network(s) or from an outside source. If the interfering RF signals emanate from a network under your control, whether it is on the same tower or several miles away, it is termed self-interference. If the opposing signals come from a network, device or other source that is not under your control, it is termed outside interference. Thus, the definition of what type of interference is being combated is not based on technology, but ownership. In licensed bands, where spectrum is relatively scarce (due to high costs) self-interference alone must be taken into account; however given a more or less known operating environment (the radio spectrum will only have signals transmitting that are under control by a single entity) proper product design and network deployment can reduce these interferes to a level where they do not impact network performance. Self-interference is not a phenomenon that is confined to licensed band operations; license-exempt bands must address the same issues. The techniques and design elements of a given product that serve to reduce and tame self-interference in licensed band operations can be applied directly to license-exempt systems. THE LICENSE-EXEMPT CHALLENGE OF INTERFERENCE In the license-exempt bands, not only must self-interference be accounted for, but, given the nature of the regulations governing these bands, external interference must be designed for as well. This can be extremely challenging, as there is no way of knowing in advance where these outside signals may be or will be sourced from, or even how strong the interfering transmissions will be relative to the desired transmission. This aspect of the license-exempt bands represents the possible downside of license-exempt network operation. Yet as potentially damaging and unpredictable as external interference can be in license-exempt networks, a properly designed and implemented broadband wireless system can make a significant difference in the performance of a network under siege from unwanted external radio transmissions. DEALING WITH COCHANNEL INTERFERENCE: PHY LAYER 1. Modulation the C/I Ratio At the most fundamental level, an interfering RF source disrupts the digital transmission by making it too difficult for the receiving station to decode the signal. How much noise or interference a digital RF transmission can tolerate depends on the modulation used. Fundamentally, modulation is the method whereby zeros and ones are communicated by varying one of three aspects of radio signal. The three portions of an RF signal that can be changed or modulated are phase, frequency and amplitude. Shirting the properties of any of these parameters can be used to communicate different states. These states, in turn, are translated to zeros and ones for binary communications. For example, with frequency modulation, if the sine wave is at frequency one, it is decoded as a zero. If the sine wave is shifted slightly
RE: [WISPA] Alvarion Comnet Radios have arrived -regardinginterference - Part 1
lol...gotta love it! I'd argue it doesn't have to be only $300 to sell. I'd pay two or three times that for such a product. But honestly that isn't that much to ask as many products are already so close...Alvarion VL being one of the closest, but still no cigar. I like what you said about developing Trango products and agree they are way past due to leapfrog back to the front of the pack. Oh those were the days when Sunstream/Trango was the undisputed leader with the début of the M5800 and then the M5830. sigh Maybe they can do it again! Best, Brad -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom DeReggi Sent: Thursday, December 28, 2006 6:05 PM To: WISPA General List Subject: Re: [WISPA] Alvarion Comnet Radios have arrived -regardinginterference - Part 1 Charles, WOW! Great Post! That covers about everything. It increases the understanding of the complexity, but it doesn't answer the ultimate question, What to use. What we really want is an efficient OFDM system, with a strong TDD w/ARQ MAC, RFThreshold, Good Noise Filtering, Packet aggregating/compressing, adeqaute CPU processing, Quality narrow beam diversity antennas, all pre-packaged in a system/box under $300. But that product does not exist today. So why doesn't a manufacturer just make it, so we can stop debating what is best, and just deploy radios! Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Charles Wu [EMAIL PROTECTED] To: 'WISPA General List' wireless@wispa.org Sent: Thursday, December 28, 2006 4:47 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1 I go to see Mickey Mouse for a few days and look where this thread has gone...wow So, my 2 cents... One of the largest concerns in the license-exempt world is the question of a system's interference robustness. However, before we can get into further detail on the pros and cons of Alvarion VL vs Canopy, CSMA/CA vs GPS, etc -- it is necessary to realize that interference as a term is extremely broad and vague, and can mean just about anything to anyone. Heck, all radios in the market have some sort of interference robustness / avoidance capability -- the trick to understanding a system's capabilities is knowing what TYPE of interference the system can actually handle. Read on...I'll talk more about each particular platform when I get some time to write Part 2 =) WHAT IS INTERERENCE? In the wireless world, interference, by definition, is a situation where unwanted radio signals operate in the same frequency channels or bands - i.e. they mutually interfere, disrupt or add to the overall noise level in the intended transmission. Interference can be divided into two forms, based on whether it comes from your own network(s) or from an outside source. If the interfering RF signals emanate from a network under your control, whether it is on the same tower or several miles away, it is termed self-interference. If the opposing signals come from a network, device or other source that is not under your control, it is termed outside interference. Thus, the definition of what type of interference is being combated is not based on technology, but ownership. In licensed bands, where spectrum is relatively scarce (due to high costs) self-interference alone must be taken into account; however given a more or less known operating environment (the radio spectrum will only have signals transmitting that are under control by a single entity) proper product design and network deployment can reduce these interferes to a level where they do not impact network performance. Self-interference is not a phenomenon that is confined to licensed band operations; license-exempt bands must address the same issues. The techniques and design elements of a given product that serve to reduce and tame self-interference in licensed band operations can be applied directly to license-exempt systems. THE LICENSE-EXEMPT CHALLENGE OF INTERFERENCE In the license-exempt bands, not only must self-interference be accounted for, but, given the nature of the regulations governing these bands, external interference must be designed for as well. This can be extremely challenging, as there is no way of knowing in advance where these outside signals may be or will be sourced from, or even how strong the interfering transmissions will be relative to the desired transmission. This aspect of the license-exempt bands represents the possible downside of license-exempt network operation. Yet as potentially damaging and unpredictable as external interference can be in license-exempt networks, a properly designed and implemented broadband wireless system can make a significant difference in the performance of a network under siege from unwanted external radio transmissions. DEALING WITH COCHANNEL INTERFERENCE: PHY LAYER 1. Modulation the C/I Ratio
Re: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1
Good stuff. In the order presented, the text makes some statements about RX threshold damping. It is a powerful tool for a higher modulation radio operating in a noisy environment, as it allows the radio to block out and ignore signals received below the preset RF Rx Threshold. By creating an artificial receiver threshold below which no RF signals are processed, the Receiver Threshold Dampening allows for the rejection of distance interferences and reduces co-location interference at the expense of a reduced coverage radius. The text above immediately follows the excellent section on C/I. Presenting in this order I felt the text might somehow imply that by setting the threshold higher than the interfering signals, that the receiver can ignore the interference (it says this in so many words). If we're talking about the Carrier-to-Interference required above the surrounding interference it's giving you the wrong impression. That would be incorrect, and since it immediately followed the section on C/I I thought I could improve a bit here. You still need every inch of the required C/I above the interference. All that is being ignored is the receiver's energy detection (and whatever impact it may cause in the MAC's channel access algorithm) from reacting to receive energy below the threshold. The interference energy is still there, and additive with desired received signal. Another way of looking at this is that you need the same margin above the receiver noise threshold as you need above the interference (you still need both SNR and C/I). In my book this is not interference rejection at all. You need the same amount of required SNR above sensitivity and C/I above interference, but the technique can be useful in masking far-away weaker signals from screwing up your channel access if you were using something like CSMA. Rich - Original Message - From: Charles Wu To: 'WISPA General List' Sent: Thursday, December 28, 2006 3:47 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1 I go to see Mickey Mouse for a few days and look where this thread has gone...wow So, my 2 cents... One of the largest concerns in the license-exempt world is the question of a system's interference robustness. However, before we can get into further detail on the pros and cons of Alvarion VL vs Canopy, CSMA/CA vs GPS, etc -- it is necessary to realize that interference as a term is extremely broad and vague, and can mean just about anything to anyone. Heck, all radios in the market have some sort of interference robustness / avoidance capability -- the trick to understanding a system's capabilities is knowing what TYPE of interference the system can actually handle. Read on...I'll talk more about each particular platform when I get some time to write Part 2 =) WHAT IS INTERERENCE? In the wireless world, interference, by definition, is a situation where unwanted radio signals operate in the same frequency channels or bands - i.e. they mutually interfere, disrupt or add to the overall noise level in the intended transmission. Interference can be divided into two forms, based on whether it comes from your own network(s) or from an outside source. If the interfering RF signals emanate from a network under your control, whether it is on the same tower or several miles away, it is termed self-interference. If the opposing signals come from a network, device or other source that is not under your control, it is termed outside interference. Thus, the definition of what type of interference is being combated is not based on technology, but ownership. In licensed bands, where spectrum is relatively scarce (due to high costs) self-interference alone must be taken into account; however given a more or less known operating environment (the radio spectrum will only have signals transmitting that are under control by a single entity) proper product design and network deployment can reduce these interferes to a level where they do not impact network performance. Self-interference is not a phenomenon that is confined to licensed band operations; license-exempt bands must address the same issues. The techniques and design elements of a given product that serve to reduce and tame self-interference in licensed band operations can be applied directly to license-exempt systems. THE LICENSE-EXEMPT CHALLENGE OF INTERFERENCE In the license-exempt bands, not only must self-interference be accounted for, but, given the nature of the regulations governing these bands, external interference must be designed for as well. This can be extremely challenging, as there is no way of knowing in advance where these outside signals may be or will be sourced from, or even how strong the interfering transmissions will be relative to the desired transmission. This aspect
Re: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference - Part 1
Again, I think they're already being made, aren't they? for 3.5GHz. Doesn't have to be final WiMAX ... I presume that all the pre-WiMAX products are OFDM and TDD. I've yet to hear of one at 900, 2.4, or 5. Anyone? Am I all wet on what the pre-WiMAX products are? I could very well be all wet, as I am only talking from what I've picked up from reading here ... and I've not had any first-hand experience with real available pre-WiMAX gear that's out there. Alvarion's got pre-WiMAX gear ... maybe Patrick can confirm, or alternatively slap me back to reality! :-) Rich - Original Message - From: Brad Belton To: 'WISPA General List' Sent: Thursday, December 28, 2006 6:16 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference - Part 1 lol...gotta love it! I'd argue it doesn't have to be only $300 to sell. I'd pay two or three times that for such a product. But honestly that isn't that much to ask as many products are already so close...Alvarion VL being one of the closest, but still no cigar. I like what you said about developing Trango products and agree they are way past due to leapfrog back to the front of the pack. Oh those were the days when Sunstream/Trango was the undisputed leader with the début of the M5800 and then the M5830. sigh Maybe they can do it again! Best, Brad -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom DeReggi Sent: Thursday, December 28, 2006 6:05 PM To: WISPA General List Subject: Re: [WISPA] Alvarion Comnet Radios have arrived -regardinginterference - Part 1 Charles, WOW! Great Post! That covers about everything. It increases the understanding of the complexity, but it doesn't answer the ultimate question, What to use. What we really want is an efficient OFDM system, with a strong TDD w/ARQ MAC, RFThreshold, Good Noise Filtering, Packet aggregating/compressing, adeqaute CPU processing, Quality narrow beam diversity antennas, all pre-packaged in a system/box under $300. But that product does not exist today. So why doesn't a manufacturer just make it, so we can stop debating what is best, and just deploy radios! Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Charles Wu [EMAIL PROTECTED] To: 'WISPA General List' wireless@wispa.org Sent: Thursday, December 28, 2006 4:47 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1 I go to see Mickey Mouse for a few days and look where this thread has gone...wow So, my 2 cents... One of the largest concerns in the license-exempt world is the question of a system's interference robustness. However, before we can get into further detail on the pros and cons of Alvarion VL vs Canopy, CSMA/CA vs GPS, etc -- it is necessary to realize that interference as a term is extremely broad and vague, and can mean just about anything to anyone. Heck, all radios in the market have some sort of interference robustness / avoidance capability -- the trick to understanding a system's capabilities is knowing what TYPE of interference the system can actually handle. Read on...I'll talk more about each particular platform when I get some time to write Part 2 =) WHAT IS INTERERENCE? In the wireless world, interference, by definition, is a situation where unwanted radio signals operate in the same frequency channels or bands - i.e. they mutually interfere, disrupt or add to the overall noise level in the intended transmission. Interference can be divided into two forms, based on whether it comes from your own network(s) or from an outside source. If the interfering RF signals emanate from a network under your control, whether it is on the same tower or several miles away, it is termed self-interference. If the opposing signals come from a network, device or other source that is not under your control, it is termed outside interference. Thus, the definition of what type of interference is being combated is not based on technology, but ownership. In licensed bands, where spectrum is relatively scarce (due to high costs) self-interference alone must be taken into account; however given a more or less known operating environment (the radio spectrum will only have signals transmitting that are under control by a single entity) proper product design and network deployment can reduce these interferes to a level where they do not impact network performance. Self-interference is not a phenomenon that is confined to licensed band operations; license-exempt bands must address the same issues. The techniques and design elements of a given product that serve to reduce and tame self-interference in licensed band operations can be applied directly to license-exempt systems
Re: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference - Part 1
It was a lot more fun back then, being on the Trango side. When Sunstream/Trango was the undisputed leader, it was easy to win a debate. Its not so easy and clear anymore. Every player is a winner and a loser from some perspective. Maybe they can do it again! I don't doubt that they can do it again. They are my first pick predicted to deliver the first true 5.8G WiMax class product usable in the US at the right price point for WISPs. The question is whether, they'll do it again soon enough. First half of 2007, can mean a lot of things. By Summer, I could have half my network/revenue converted to Alvarion, and be to late to change course. But then again, first half of 2007 could mean February, which could be a different situation. The only downside I saw in the new planned Trango product was it was limited to 10Mhz channels. I liked the options for 10Mhz, but I didn't like it mandatory. 10Mhz requirement most likely would result in replacing existing gear with gear that delivered near the same capacity after all considered. So where it would be the best choice for new sectors, it would not necessarilly justify change of sector. My contracts are per antenna, not per spectrum channel. I'm now going back trying to renegotiate my agreements to handle more antennas for the same price, but thats not easy to do. The idea was to pay top dollar upfront, and make my money when I put high speed gear and more customers on net, WITHOUT increasing my colocation fees. If my colocation fees increase, to add more antennas, I don't become more profitable by deploying the gear. Its simple math. But then again, if I can successfully renogiate my leases, it could be a blessing, allowing me to build in redundant sectors, a legacy Trango feature and design to our network that I was never able to take advantage of due to lack of spectrum. But truthfully, the real winner is going to be the manufactuer that delivers legal compliant 5.4Ghz.into their platform. It will be nice to have virgin spectrum again like 5 years ago. (even if limited to 1 watt). 5.4Ghz is where staying 20Mhz is a logical choice. Its going to be hard to get that 25db SNR with 1 watt radios, but the idea would be use all the short range links with 5.4, and all the long range links with 5.8. If I had to start using a whole new platform (not downword compatible), paying for duplicate antennas, why not do it with 5.4G under that model, and maximize the use of all available resourses? It would make a more logical migration plan. Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Brad Belton [EMAIL PROTECTED] To: 'WISPA General List' wireless@wispa.org Sent: Thursday, December 28, 2006 7:16 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference - Part 1 lol...gotta love it! I'd argue it doesn't have to be only $300 to sell. I'd pay two or three times that for such a product. But honestly that isn't that much to ask as many products are already so close...Alvarion VL being one of the closest, but still no cigar. I like what you said about developing Trango products and agree they are way past due to leapfrog back to the front of the pack. Oh those were the days when Sunstream/Trango was the undisputed leader with the début of the M5800 and then the M5830. sigh Maybe they can do it again! Best, Brad -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom DeReggi Sent: Thursday, December 28, 2006 6:05 PM To: WISPA General List Subject: Re: [WISPA] Alvarion Comnet Radios have arrived -regardinginterference - Part 1 Charles, WOW! Great Post! That covers about everything. It increases the understanding of the complexity, but it doesn't answer the ultimate question, What to use. What we really want is an efficient OFDM system, with a strong TDD w/ARQ MAC, RFThreshold, Good Noise Filtering, Packet aggregating/compressing, adeqaute CPU processing, Quality narrow beam diversity antennas, all pre-packaged in a system/box under $300. But that product does not exist today. So why doesn't a manufacturer just make it, so we can stop debating what is best, and just deploy radios! Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Charles Wu [EMAIL PROTECTED] To: 'WISPA General List' wireless@wispa.org Sent: Thursday, December 28, 2006 4:47 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1 I go to see Mickey Mouse for a few days and look where this thread has gone...wow So, my 2 cents... One of the largest concerns in the license-exempt world is the question of a system's interference robustness. However, before we can get into further detail on the pros and cons of Alvarion VL vs Canopy, CSMA/CA vs GPS, etc -- it is necessary to realize that interference as a term is extremely
RE: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference- Part 1
Alvarion's got actual WiMAX gear Rich. Our WiMAX-certified BreezeMAX 3500 is being deployed in over 100 commercial networks along with about 120 trials. In the U.S. we are selling and deploying early BreezeMAX 2500 and BreezeMAX 2300 to a handful of operators. These are TDD 802.16e-ready solutions and they will be certified when the WiMAX Forum opens up .16e certification testing. Some call BreezeACCESS pre-WiMAX, but that is only true to the extent that it uses OFDM and has a host of other features that some might call WiMAX-like. I am personally not fond of pre/like/kinda, etc. UNLESS the system is real WiMAX and just awaits the certification process, such as is the case with BreezeMAX 2300 and BreezeMAX 2500. BreezeMAX 3500 is already certified. Anything called BreezeMAX was designed from the ground up to support WiMAX profiles and will ultimately be WiMAX-certified. Anything in our line NOT called BreezeMAX will not ever be WiMAX-certified. Patrick Leary AVP WISP Markets Alvarion, Inc. o: 650.314.2628 c: 760.580.0080 Vonage: 650.641.1243 [EMAIL PROTECTED] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rich Comroe Sent: Thursday, December 28, 2006 5:31 PM To: WISPA General List Subject: Re: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference- Part 1 Again, I think they're already being made, aren't they? for 3.5GHz. Doesn't have to be final WiMAX ... I presume that all the pre-WiMAX products are OFDM and TDD. I've yet to hear of one at 900, 2.4, or 5. Anyone? Am I all wet on what the pre-WiMAX products are? I could very well be all wet, as I am only talking from what I've picked up from reading here ... and I've not had any first-hand experience with real available pre-WiMAX gear that's out there. Alvarion's got pre-WiMAX gear ... maybe Patrick can confirm, or alternatively slap me back to reality! :-) Rich - Original Message - From: Brad Belton To: 'WISPA General List' Sent: Thursday, December 28, 2006 6:16 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived-regardinginterference - Part 1 lol...gotta love it! I'd argue it doesn't have to be only $300 to sell. I'd pay two or three times that for such a product. But honestly that isn't that much to ask as many products are already so close...Alvarion VL being one of the closest, but still no cigar. I like what you said about developing Trango products and agree they are way past due to leapfrog back to the front of the pack. Oh those were the days when Sunstream/Trango was the undisputed leader with the début of the M5800 and then the M5830. sigh Maybe they can do it again! Best, Brad -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom DeReggi Sent: Thursday, December 28, 2006 6:05 PM To: WISPA General List Subject: Re: [WISPA] Alvarion Comnet Radios have arrived -regardinginterference - Part 1 Charles, WOW! Great Post! That covers about everything. It increases the understanding of the complexity, but it doesn't answer the ultimate question, What to use. What we really want is an efficient OFDM system, with a strong TDD w/ARQ MAC, RFThreshold, Good Noise Filtering, Packet aggregating/compressing, adeqaute CPU processing, Quality narrow beam diversity antennas, all pre-packaged in a system/box under $300. But that product does not exist today. So why doesn't a manufacturer just make it, so we can stop debating what is best, and just deploy radios! Tom DeReggi RapidDSL Wireless, Inc IntAirNet- Fixed Wireless Broadband - Original Message - From: Charles Wu [EMAIL PROTECTED] To: 'WISPA General List' wireless@wispa.org Sent: Thursday, December 28, 2006 4:47 PM Subject: RE: [WISPA] Alvarion Comnet Radios have arrived - regardinginterference - Part 1 I go to see Mickey Mouse for a few days and look where this thread has gone...wow So, my 2 cents... One of the largest concerns in the license-exempt world is the question of a system's interference robustness. However, before we can get into further detail on the pros and cons of Alvarion VL vs Canopy, CSMA/CA vs GPS, etc -- it is necessary to realize that interference as a term is extremely broad and vague, and can mean just about anything to anyone. Heck, all radios in the market have some sort of interference robustness / avoidance capability -- the trick to understanding a system's capabilities is knowing what TYPE of interference the system can actually handle. Read on...I'll talk more about each particular platform when I get some time to write Part 2 =) WHAT IS INTERERENCE? In the wireless world, interference, by definition, is a situation where unwanted radio signals operate in the same frequency channels or bands - i.e. they mutually interfere, disrupt or add to the overall noise
