Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: [STDS-802-16] Clarification regarding SS power level control



Only one more comment.  The final 4dB of error will also be reduced by
subsequent BS commands, and relative error diminishes to +/- 0.5dB for
the final error (relative to the BS's capability to measure power)
      -----Original Message-----
      From: Raja Banerjea [mailto:RBanerjea@PROXIM.COM]
      Sent: Monday, April 19, 2004 9:14 AM
      To: STDS-802-16@LISTSERV.IEEE.ORG
      Subject: Re: [STDS-802-16] Clarification regarding SS power
      level control

      The power control method is a closed loop method where the
      Base station asks for further power control corrections if
      required. If the base station requests the subscriber station
      in the RNG-RESP to increase the power level by 30dB the SS
      should increase it by 30dB with a relative accuracy of 4dB.

      If the Base station is going to increase the power of the SS
      in 5 steps and the BS requests the SS to increase the power
      by 8dB the SS will increase it by 8dB with a relative
      accuracy of 4dB. In the subsequent RNG-RESP message the BS
      instead of requesting a power increase of 8dB will request
      for 8dB+(relative accuracy). Therefore after each increase
      requested from the BS the relative accuracy should be 4dB.

      This assumes that the BS can make an accurate measurement of
      the SS's power increase.

      Any comments ?

      Regards,

      -Raja

       
            -----Original Message-----
            From: Crozier, Eugene
            [mailto:Eugene_Crozier@SRTELECOM.COM]
            Sent: Monday, April 19, 2004 6:26 AM
            To: STDS-802-16@listserv.ieee.org
            Subject: Re: [STDS-802-16] Clarification
            regarding SS power level control

            My understanding of this is that the step size
            should be greater than 1 dB but less than 8 dB
            (I'd assumed for the relative accuracy that the
            50% of the step size can be no more than 4 dB),
            but the number of steps is based on the step size
            and the relative accuracy to achieve the minimum
            control range, so for 1 dB steps, the number of
            steps can be between 60 and 20 (30/0.5 and
            30/1.5) for a 30 dB range, and for 8 dB step size
            the number of steps between 8 and 3 for the 30 dB
            range.

             

            Regards

             

            Eugene Crozier
                  -----Original Message-----
                  From: Eyal Verbin
                  [mailto:everbin@AIRSPAN.COM]
                  Sent: Monday, April 19, 2004 8:22 AM
                  To: STDS-802-16@listserv.ieee.org
                  Subject: [STDS-802-16] Clarification
                  regarding SS power level control

                  Power level control for the OFDM PHY
                  is defined in section 8.3.9.1:

                  " For an SS not supporting
                  subchannelization, the transmitter
                  shall support a monotonic power level
                  control of 30 dB minimum. For an SS
                  supporting subchannelization, the
                  transmitter shall support a monotonic
                  power level control of 50 dB minimum.
                  The minimum step size shall be no
                  more than 1 dB. The relative accuracy
                  of the power control mechanism is
                  +/-50% of the step size in dB, but no
                  more than 4 dB. As an example, for a
                  step size of 5 dB the relative
                  accuracy is 2.5 dB. For a BS, the
                  transmitter shall support a monotonic
                  power level control of 10 dB
                  minimum." 

                  Looking at the SS (subchannelization)
                  for example, it is possible to go
                  from Min power to Max power either in
                  5 steps of 8 dB or in a single step
                  of 50dB. In the first option the
                  accumulated offset can reach 5*4dB
                  (20dB) wheras in the second option
                  the tolerance is limited to 4dB.

                  Does anyone have a more clear
                  interpretation of this text?

                  Eyal Verbin