The algorithm updates the records of the remaining power, codes, and HS-SCCH quantity If

EPF Algorithm

Step 4 The algorithm updates the records of the remaining power, codes, and HS-SCCH quantity If

all of these resources are available and another MAC-hs queue is waiting for resource allocation, then the algorithm repeats the previous steps. Otherwise, the algorithm ends the handling.

----End

4.5.2 Determining the TBS

max

4 User Plane HSDPA

Issue 02 (2009-06-30)

Δ

+

Γ

+

=

−PDSCH CPICH HS

P

where

PCPICH is the transmit power of the CPICH.

is the measurement power offset (MPO). It is specified by the parameter

HsPdschMPOConstEnum on the RNC side and sent to the NodeB and UE.

Γ

is the reference power adjustment. It is set to 0 in most cases. For details, see 3GPP TS 25.214.

Δ

On this assumption, the UE reports the CQI through the HS-DPCCH to the NodeB. The CQI indicates the channel conditions of the UE. A higher CQI indicates that the channel quality is better and therefore the NodeB can send a larger MAC-hs transport block to the UE. The NodeB creates a CQI mapping table for each UE category. For each CQI, this table provides a corresponding MAC-hs TBS and a modulation scheme based on the assumed power (

P

_HS₋_PDSCH

=P

_CPICH

+Γ+Δ

) and the number of channelization codes. Such combinations ensure that the block error rate (BLER) of MAC-hs transport blocks on the Uu interface does not exceed 10%. The table is obtained on the basis of many simulations and test experiences. It plays a very important role in HSDPA resource allocation.

If the available power of the HS-PDSCH is higher than the assumed power, a larger MAC-hs TBS is allowed, which is equal to the TBS corresponding to the adjusted CQI. The adjusted CQI is calculated as: reported CQI + (available power - assumed power). In this way, the algorithm provides higher transmission rates.

If the available power is lower than the assumed power, the supported MAC-hs TBS needs to be reduced to the one corresponding to the adjusted CQI. The adjusted CQI is calculated as:

reported CQI – (assumed power - available power). In this way, the algorithm ensures

transmission correctness.

Thus, the algorithm can determine the TBSmax of the UE in the current cell after obtaining the

CQI reported by the UE, available power, and available codes.

Here is an example. Assume that the CQI reported by the UE is 5, the available power is equal to the assumed power, and the number of available codes is 4. Then, the TBSmax is 3,762 bits

4-13

4.5.3 Determining the TBS

used

, Modulation Scheme, Power, and

Codes

If the data buffered in the MAC-hs queue is much enough to fill the space for carrying data in a transport block with the TBSmax, then the TBSmax is taken as the TBS to be used (TBSused).

Accordingly, the modulation scheme corresponds to this TBS is taken as the one to be used. The algorithm then determines the power and channelization codes to be used, according to the method mentioned in section 4.5.2 "Determining the TBSmax."

The TBSmax, however, may be much larger than the data buffered in the MAC-hs queue. If

this TBS is used, too many padding bits reduce the spectrum efficiency. To solve this problem, the algorithm searches the CQI mapping table backward for the CQI or the number of codes so as to obtain the most appropriate TBS and the corresponding modulation scheme. This TBS should be the smallest one in the TBS set that can carry the buffered data. The power and code resources determined through backward searching are taken as the ones for allocation. Huawei supports three backward-searching methods, which are specified by the parameter

RscAllocM on the NodeB side:

If the parameter is set to Code_Pri, the algorithm prefers the use of codes. Under the precondition that the transport block with the TBS is large enough to carry the buffered data, the algorithm first reduces the power. If the corresponding CQI decreases to the smallest one but the precondition is still met, the algorithm attempts to reduce the number of codes. This setting is applicable the outdoor macro base station with limited power.

If the parameter is set to Power_Pri, the algorithm prefers the use of power. Under the precondition that the transport block with the TBS is large enough to carry the buffered data, the algorithm first reduces the number of codes. If the number of codes decreases to 1 but the precondition is still met, the algorithm attempts to reduce the power. This setting is applicable to indoor application with limited codes.

If the parameter is set to PowerCode_Bal, the algorithm balances the use of power and the use of codes. Under the precondition that the transport block with the TBS is large enough to carry the buffered data, the algorithm reduces the power and codes in a balanced mode. This setting protects the codes or power from being used up, thus improving the resource usage and increasing the cell capacity.

The following figure shows the backward-searching methods used when the parameter is set to Code_Pri or Power_Pri.

The following figure shows the backward-searching methods used when the parameter is set to PowerCode_Bal.

4 User Plane HSDPA

Issue 02 (2009-06-30)

4.5.4 Determining the Number of MAC-d PDUs

TBSused is the used MAC-hs PDU size. It contains a MAC-hs header and the MAC-hs payload.

The size of MAC-hs payload is equal to the total size of MAC-d PDUs. Assume that S represents (TBSused – (MAC-hs PDU header size))/(MAC-d PDU size). Then, round down S to the nearest integer to obtain the number of MAC-d PDUs to be transmitted.

5-1

5

QoS and Diff-Serv Management

This chapter consists of the following sections: QoS Management

Diff-Serv Management

apping and Configuration

5.1 QoS M

e the

servi The requirements

ires higher service rates to provide better user experience. es shorter delay to provide better user experience.

ctions. The following table

l ons bet nd

T ions b n HSDPA functions an QoS indicators

QoS Parameter M

anagement

Th goal of service-oriented QoS management is to improve user experience by reducing ce delay and BLER and by increasing the service rate and continuity.

for oS vary according to the type of service:

The conversational service (including the CS voice and VoIP) has a relatively high requirement for service delay and a certain requirement for BLER.

The streaming service has a requirement for guaranteed bit rate (GBR).

The FTP service has a very high requirement for BLER and error-free transmission. In addition, this service requ

The HTTP service has a high requirement for error-free transmission and a certain requirement for response delay. In addition, this service requir

HSDPA QoS management is implemented by related HSDPA fun ists the relati ween HSDPA functions a QoS indicators.

In document HSDPA Parameter Description (Page 35-39)