Subject: Re: [MOBILE-IP] intra-RAN diversity with dynamic anycasting...

From: James Kempf <[email-masked]>
Date: Thu, 4 May 2000 15:35:29 -0700

Theo,

>I cannot see how you intend to effect power control on the MN since you
>have no control over the mobility pattern of the MN. For instance lower
>power on the MN may be effected if the MN is relatively close to the BS
>and the air interface is relatively quiet. I would probably opt for the
>word 'compliance' to power transmission requirements based on
>(distance,velocity,height,direction) vector. The degree of compliance to
>power control on the BS should be affected in some non-linear way by
>that vector.
>

I'm not entirely sure what your message was referring to, but it is
my understanding that current and future CDMA protocols have a
very tight coupling between the mobile terminal and the RAN in
terms of power control. The RAN gateway (to use the terminology from our draft)
basically adjusts the power incrementally in order to balance the signal
strength to the base stations to which the MN is transmitting. So it is not a
question of whether the RAN can or can not affect the power on the MN, it, in
fact, currently does.

                jak

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From: Theo PAGTZIS <[email-masked]>
Date: Thu, 4 May 2000 23:56:54 +0100

Jak,

> question of whether the RAN can or can not affect the power on the MN, it, in

My initial understanding from the draft was that power control was attempted to be
exerted on the MN by the BTS in terms of power savings rather than
balancing of signal strength from the MN to each individual BTS to which the MN is
Tx-ing...

Given some random mobility pattern I was finding difficult to see how you manage
to yield power savings on the MN in terms of some control protocol (since the
function was not stipulated by the BTS but by the RAN gateway.... )

It is now clear to me that we are talking about signal strength manipulation on
the BTS effected by the RAN gateway, which reflects on the power levels of
transmission on the part of the MN...  How does the RAN gateway exert such control
over the BTS(s). What protocol does it employ..?

Theo

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From: Arthur Ross <[email-masked]>
Date: Thu, 4 May 2000 16:11:50 -0700

>question of whether the RAN can or can not affect the power on the MN, it, in
Correct. The power is adjusted very rapidly (800 updates per second in the
original ANSI-95 standard) by a closed loop mechanism in rather small steps
(1 dB or less). Last I heard actual field measurements had found the rms
error between received power and the loop setpoint to be roughly +/- 2 dB
... pretty good when you consider the enormous dynamic range of path loss
that can be experienced in these systems.

And that control mechanism does take into account the soft HO. Only if ALL
participating base stations in the SHO say "UP" does the MS increase power.
The intent is to keep the power at the level needed for adequate QoS and NO
HIGHER. This tight power control is one of the keys to the high spectral
efficiency/capacity of CDMA.

'Course this is all predicated on continuous transmission in both
directions that permits the closure of the loop.

   -- A