(1)有關目前PrxLoadMarginDCH參數設定值為10 dB，為避免上鏈負載成長過高，造成過大的細胞呼吸效應，網維提出修訂建議。經NSN 測試後建議一併調整PrxTarget/PrxOffset、DeltaPrxMaxUP等參數。NSN change

the related parameters of the whole network (Due to network activity, RN291, 28, 281, 61, 611, 411 are not

changed yet), find that HSDPA Accessibility Failure due to UL-DCH can be improved while there are the

increment of BTS and Iub failure due to higher traffic. Please NSN roll out this setting in remaining RNC. And

propose the monitor report in the next meeting after roll-out.

3G品質提昇及技術研討會

細胞呼吸效應---- 一旦資料傳輸速率或使用人數增加時，則系統話務負擔增加，因此要降低系統負載，就必須縮小細胞涵蓋區域，換言之，當細胞間的干擾增大，為維持系統容量，實際的細胞涵蓋區域會需要縮小，也就是細胞呼吸效應。

PrxLoadMarginDCH Range 0...30 Step 0.1 Default value 0 dB

For the interference domain, this parameter defines the maximum capacity for the throughput

based traffic load that is allowed for the uplink DCH traffic in the cell. The parameter introduces a

protection margin against the possible estimation errors in the interference based DCH resource

allocation. If the received noise power level is overestimated, and because of that the interference

of the DCH users is underestimated, it may result to overload which means possible loss in the

uplink coverage and the network stability. When the DCH traffic load exceeds the threshold defined

with the parameter, the RNC initiates UL overload control actions to reduce the uplink PS

interactive and background DCH traffic.

PrxNoise of WCEL - Value of the

parameter is defined in the

relation to the value of the

parameter PrxNoise. ,

PrxLoadMarginDCH of WCEL -

Value of the

PrxLoadMarginMaxDCH must be

higher than or equal to the value

of the PrxLoadMarginDCH.

DCH traffic load threshold

Prx

To

tal

Interference margin for the minimum

UL DCH load

NoiseRiseTarget=

Prx_target/PrxNoise

Prx_Noise

RT RAB is not

admitted

RAB is not

admitted

PrxOffset

DeltaPrxMaxUP

The packet scheduler takes care of scheduling radio resources for non real-time radio bearers for both the uplink

and the downlink directions. Packet access is implemented for dedicated (DCH) as well as common control

transport channels (RACH/FACH).

The packet scheduler and the medium access control (MAC) layer together make the decision regarding which

type of channel to use in the downlink direction. As regards the uplink direction, the UE decides which type of

channel to use, on the basis of parameters controlled by the network. The channel type selection is fast and takes

into account the amount of data in the buffer and the current radio conditions. Uplink data transmission on

dedicated channel is initiated when UE sends a capacity request. In the downlink it is the MAC layer that requests

transmission

real-time traffic +

interference from other cell users +

noise = non-controllable load

For Real time traffic

The load caused by best effort non

real-time traffic is called controllable

load.

For Non real time traffic

The packet scheduler and the medium access control (MAC) layer together make the decision regarding which

type of channel to use in the downlink direction.

the UE and BTS capabilities ;the properties of the radio access bearer ; the current RNP parameter settings ; the availability of the capacity in RAN

The amount of scheduled capacity depends on:

the UE and BTS capabilities

the properties of the radio access bearer

the current RNP parameter settings

the availability of the capacity in RAN

Packet scheduling • To determine the available radio interface resources for non real time radio bearer.

• To share the available radio interface resources between non real time radio bearers.

• to monitor the allocations for non real time radio bearers.

• To initiate transport channel type switching between common, shared and dedicated

channels when necessary.

• To monitor the system loading.

• To perform load control actions for the non-real-time radio bearers when necessary.

HSDPA_BTS transmission power

The principle of the BTS based dynamic power allocation algorithm is illustrated in the following figure:

Figure: BTS based power allocation

PMax is the cell maximum output power defined by the minimum of the following two parameters: PtxCellMax and

MaxDLPowerCapability. PtxCellMax is the operator adjustable management parameter and MaxDLPowerCapability is the

maximum output power capability received from the base station. PtxTargetPS stands for the NRT DCH scheduling target,

which is dynamically adjusted by the RNC (it is not an operator adjustable parameter but the name for the parameter internally

used and adjusted by the RNC). PtxTargetPSMax and PtxTargetPSMin are the maximum and minimum values for the PtxTargetPS,

respectively. Both values can be adjusted by the operator (PtxTargetPSMax and PtxTargetPSMin management parameters). The

figure assumes that the WCEL-parameter PtxMaxHSDPA is set to not restrict the HSDPA power allocation in the BTS.

The packet scheduler is located in the Interface Control and Signalling

Unit (ICSU) of the serving radio network controller (SRNC). In the drift

RNC, non real-time bearers are handled as real-time bearers, and

therefore are not taken into account in packet scheduling. The figure

below shows the logical working environment of the packet scheduler.

Figure: Logical working environment of the packet scheduler

When the own cell throughput exceeds a particular level, the interference estimations are initiated and the planned interference target is

applied in the uplink DCH resource allocations.

transport channel; TrCH

channel offered by the physical layer to the data link layer for data transport between peer physical layer entities

Maximum bit rate of HS-DSCH MAC-d flow

The maximum user bit rate of the HS-DSCH MAC-d flow used in the resource reservation for the HS-DSCH MAC-d flow is the smallest of the

following values:

The maximum bit rate based on UE capability

The value of the MaxBitRateNRTMACdflow management parameter. The parameter does not limit the maximum instantaneous bit rate on the

air interface. The value of the parameter is compared to the user bit rate of the HS-DSCH MAC-d flow excluding MAC-hs header, RLC header

and padding.

The maximum bit rate in RAB parameters. This condition is checked only if the HSDPAPeakRateLimitRABMax management parameter is set

to value 1 (Limitation is active).

Call Setup

Basic Mobile

Originating Call

Diagram

MAC 結構

Transport Channel Type Switching

C/T

MUX

C/T

MUX

Deciphering

UL: TFC selection

Ciphering

MAC Control DCCH DTCH DTCH

To MAC-hs

To/from MAC-c/sh

DCH DCH

MAC-d

MAC-d 的架構