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To: mightylakers who wrote (110834)	1/12/2002 1:58:11 PM
From: slacker711	Read Replies (1) \| Respond to of 152472

I'm not sure if I am reading this right...it seems like COM DEV believes that 1xEV-DO will be able to provide 1Mbps speeds in a typically loaded system (not throughput but a single user speed). This seems MUCH higher than I would have expected. Hmmm....they use the word instantaneous. Since 1xEV-DO splits up users in the time domain, maybe I should be multiplying the speed by the percentage of slots that user would have for that one second. comdev.ca Q. In a recent article I read they mention the fact that, under real useage, M/ERGY functions at about 800 kbps. They also mention the fact that if there are two users in the same cell, they have to share this speed. In other words, if there are 10 simultaneous users, then they effectively end up with an 80 kbps speed while roaming. Is this correct? (Submitted January, 2002) A. Remember that M/ERGY is a packet switched network. No one actually occupies a circuit as in the case of a circuit switched network. Everyone is "always on" the network and shares a common pipe into which they insert their data packets and from which they receive the data packets addressed to them. It is thus true that the total capacity of each M/ERGY base station is shared among all the users connected to it. The grade of service the customer actually sees, therefore, varies with the number of subscriber instantaneously transmitting and receiving at the same time. It will also vary according to how the service provider loads the system and the distance from the base station and the speed of the user. (As a mobile user moves faster or begins to go out of range of the base station, more packets will need to be re-transmitted and total throughput will slow toward 100 Kbits/sec). However, I am told that for a stationary user within the specified 3-5 km range of a base station, assuming the operator loads the network as recommended, the minimum instantaneous down link data speed seen by user should be in the order of one Mbits/sec over the last mile link M/ERGY provides. In practice, speed limitations of the Internet backbone may result in slower maximum end-to-end service in the order of 400-800 Kbits/sec or less, but that is an Internet limitation not an M/ERGY limitation.

To: mightylakers who wrote (110834)	1/12/2002 2:54:41 PM
From: Eric L	Read Replies (2) \| Respond to of 152472

Lakers, re: "throughput" again << The speed issue is really a very fuzzy concept overall. >> In mobile wireless telephony (mobile or portable) it certainly is. It is considerably less fuzzy with fixed wired connections. In fact it is very consistent. I know rather precisely what to expect from a wired modem connection in my home through my long standing exceptional local ISP. I know what my ADSL modem and V.90 modems will deliver in my home or office (which is attached to my home) over Verizon copper. and until I recently installed XP (the version of the Lucent monitoring tool I use doesn't yet support XP) I knew precisely what connection rate and throughput I was achieving in a given session from a particular web site. If my connection rate and or throughput drop the Verizon techs get a call, look at my logs, and they splice or swap a cable because the darned squirrels chewed the fabric and its humid and the copper is singing. Alternatively I upload logs to my ISP, and they diagnose, although in the last 4 years the problem has never been on their end (except for feeds to them) but they have been helpful in helping diagnose a line problem. That will not necessarily be the case in the early going with 1xRTT and I will use 1xRTT (assuming security and authentication pass muster for my Domino based corporate intranet) in a mobile or portable environment, but I suspect it will be some time before I eliminate ADSL with dial backup for fixed home or office although I'll certainly evaluate it. << There are two parts of the same thing, network throughput and the speed that a user gets. >> All I'm interested in as a user is the speed I get, and the consistency of that speed. << The biggest challenge with networks is how to optimize the scheduler for all the users. Just like running a horse racing, you need a good horse and a good jockey combo to win. >> With a wired connection, 1.2 miles from the Verizon switch, an exceptional ISP - matched modems and a modem to user ratio of better than 8:1 and great high speed feeds (actually 2 exceptional ISP's counting the company provided secured AT&T Worldnet connections I use on the road), well tuned modems, and great inside wiring. I have great horses, great jockeys and exceptional QoS. Hopefully Verizon Wireless is a good horse and has a good jockey on the wireless data side. Sprint PCS simply does not have adequate coverage where I travel to consider them for my primary wireless need - voice. My corporation has determined the same thing so we use AWS and Verizon corporately (with VoiceStream for overseas travel). Sprint PCS doesn't even have adequate coverage where I reside and I am 1.4 miles from the major east coast north-south interstate that essentially stretches from Maine to Florida. A Sprint PCS user can get a "fair" connection if he walks outside my office, sits on the front steps, and fiddles with the orientation of the handset. As the PCS website says: The location you selected is only partially covered by the Sprint PCS Network. You may be unable to use your Sprint PCS Phone, or certain features may be unavailable in this area. << the average TP of a sector is about anywhere between 100kbps to 250kbps depending on number of users, distribution of the users, radio environment, applications and scheduling policy. >> 100 to 250 kbps average TP for the sector with Release 0? << depending on number of users >> That’s just what I need - trying to surf at 9:15 in the evening with my wife and all my neighbors and all the students in the sorority and fraternity houses in my sector all talking on their free Verizon minutes. As I say ... I suspect I'll be on copper for some time, and I really don't know what to expect from 1xRTT in the early going. I'm sure it will be much better than IS-95A for portability (phone as modem). I sure hope so. Right now that's "only in a pinch". - Eric -