Channel Question

[ChaosThyre81]

Me and my brother both have Sprint. My phone is usually on channel 450 whereas his on on channel 500. Now, sometimes when we make calls we will be on the same tower, but different channels. So, does this mean that a PN Offset can have more than one channel??

Thanks! Happy Holidays =)

[larry]

Not sure about this but I believe Sprint places certain phones on different channels according to either the MDN or something else. If I'm wrong telecomjunkie will jump in an explain it better.

[ChaosThyre81]

Yea, my phones always on channel 450 but sometimes switches when I make a call. His is on 500. Now, say we're both on the same PN Offset while on a call but on different channels, is the PN Offset divided into a few channels? The frequencies my phone 'listens' to are broken up according to channel?

[TelcomJunkie]

Not sure about this but I believe Sprint places certain phones on different channels according to either the MDN or something else. If I'm wrong telecomjunkie will jump in an explain it better.

Correcto, it's a way of load balancing.

Yea, my phones always on channel 450 but sometimes switches when I make a call. His is on 500. Now, say we're both on the same PN Offset while on a call but on different channels, is the PN Offset divided into a few channels? The frequencies my phone 'listens' to are broken up according to channel?

In Detroit, Sprint is on PCS block B would have it using channels 425-675. So the channels you're seeing match up. What happens is that there is a code generated based on how many carrier frequencies (carrier frequencies are explained below*) are typically present in a market, lets say two. When your phone number is hashed through this code it will tell your phone which carrier frequency to use if it's available. So if your phone defaults to carrier one, then if channel 450 (If that's the main carrier channel in your area) is being broadcast and your phone receives it then that's what you'll lock on to. If the phone defaults to frequency two or three (Say 500 or 550) then if it picks up either 500 or 550 at all that's what it will lock on to, avoiding channel 450 unless no other frequency is being broadcast.

With this you could say a phone that hashes to the first carrier frequency gets better reception than the phone that defaults to the second. Simply because the one defaulting to the second will lock on to a one bar signal if it's present and ignore the five bar one.

On the PN offset, that only identifies one sector of a particular site. Numerous carrier frequencies can be transmitted from the same PN offset.

*A carrier frequency, in simplest terms is a channel that is always transmitting the site information and other information too. Your phone finds the strongest site (All transmitting on the same channels, just different data is being sent from each site) and locks onto it. It is constantly comparing different sites.

[ChaosThyre81]

Wow, thanks for the really indepth reply. It's exactly what I was looking for. Sweet. Another question, sometimes when my phone is in field test mode, I'll dial out, and it sometimes switches from channel 450 to 500 then the call goes thru. Does the tower tell the phone to change channels in order to keep balance? And sometimes it stays on 500 for about 30 seconds then switches back. Would switching between channels be considered hard handoff?

[TelcomJunkie]

Wow, thanks for the really indepth reply. It's exactly what I was looking for. Sweet. Another question, sometimes when my phone is in field test mode, I'll dial out, and it sometimes switches from channel 450 to 500 then the call goes thru. Does the tower tell the phone to change channels in order to keep balance? And sometimes it stays on 500 for about 30 seconds then switches back. Would switching between channels be considered hard handoff?

There is nothing preventing an phone that defaults to carrier one from locking onto carrier two if it's the only frequency available. What happens is it will try to lock on to it's preferred frequency and once it see it's again it will jump back and forth depending on the signal levels it's getting from the nearby sites.

[ChaosThyre81]

Thanks, I do appreciate you taking your time to reply to my endless questions! Switching between channels would be hard handoff?

Something I noticed yesterday at my cousins house, when I make a call, it would switch from channel 450, to 500, then back to 450. I'm sure iff too many people are on channel 450 the tower can tell the handset to use channel 500 if there are less people using that channel, load balancing?

Also, another thing I noticed, then I'm talking and the phone changes channels, you can hear a brief moment of silence but after the channel change if I'm talking constantly into the handset, the sound on the other end (landline) is just silence, then if I stop talking them resume, it goes back to normal. Does this have something to do with the EVRC thinking that the sound of my voice is background noise, and once I stop talking and resume everything is ok?