Improving CDMA handoffs? 1900 roam in Atlanta?

[TKR]

I have been satisfied overall with Sprint (metro Atlanta) - I just want to see them to continue to improve. I guess yesterday was the twilight zone for me. Two dropped calls while driving on I-75. I could not replicate either one this morning.

The second dropped call happened in downtown Atlanta as I rounded a sharp curve as the interstate snakes through downtown near Ga Tech. Obviously a handoff zone. Anyway, the call abruptly dropped and then the phone could not find service for about a minute. I suspect a local tower was off line as I usually have signal there. My dual band 4000 then went into DIGITAL ROAM. Shocked, I immediately dialed 611 to see what system I was on, but by then it re-connected to Sprint. The digital roam was so brief, I don't know if it was real, or if my phone was momentarily confused. I have never seen it before. If it was real, then I suspect it's lower in the PRL priority than Verizon analog.

Improving handoffs?
On a related subject, I have been thinking that CDMA handoffs perhaps could be improved. I am talking about situations where because of terrain, buildings, etc a call drops but then the phone immediately finds a good signal with the next tower (that previously had presumably been blocked). As I understand it, a tower will not start communicating to a phone until the phone first tells it that it is there. Only then will a link be established. This process appears to introduce a delay factor. When terrain is involved, my theory based on observation is this factor alone can cause drops.

My idea would modify the process somewhat by introducing some intelligence within the base station network so that the next logical tower(s) that the system thinks the phone will likely be going to begins to expect the arrival of the phone into its zone. That way the network would then already allocate a splice of spectrum from that tower to that phone, so that the phone does not have to be surprised by a sudden loss of the former tower, only to discover that the next tower had already just come into range. This phenomenon of "sudden drop, oh wait here's a good signal" seems to happen frequently enough in the Atlanta area.

I'm a CDMA novice - so I welcome comments as to the feasibility of this concept.

Tom
Sanyo 4000

[larry]

Tom,

Good post. CDMA is supposed to have the best handoffs out of all the technologies but I have also on ocassion seen just what happened to you. There used to be an antenna that would drop calls even though I had a 4 bar signal. The problem was that it was not recognizing and handing off to a new tower which was just added. I think it's just a matter of Sprint not fine tuning their antennas properly. Each antennas has to be fine tuned and programmed whether or not to handoff to another antenna and at what point. This is usually done soon after the tower is constructed. They send out a drive team to test and make those adjustments. Sometimes it is not done 100% correctly. It sounds like it's something that could be fixed but of course it is up to Sprint to send someone out to fix them. You could always try the old trouble ticket and describe the problem in detail and who knows, maybe they will try and fix it

[IdiOTeQnoLogY]

that is how cdma soft handoffs work. the tower handing the call off does communicate with the tower the call is being handed off to.