-HSDPA-Parameter-1

HSDPA Parameter:

HSDPA Parameter Sonny Rafiq

Overview:

Overview High Speed Downlink Packet Access In P4, 4.32 Mbps is possible and up to 14 Mbps in P5 Best effort service HSDPA P4 is time shared HSDPA has Link Adaptation QPSK 16 QAM Hybrid ARQ Scheduling Short TT1 (2 msec)

Channel Structure:

Channel Structure R5 of 3GPP standard introduces 3 new channels that support HSDPA. One HS-DSCH (High Speed Downlink Shared Channel) Mapped to up to 15 (5 in P4) HS-PDSCH SF 16 Dynamic allocation every 2 msec Time sharing only in P4. Code sharing later One HS-SCCH (High Speed Shared Control Channel) in P4 Control information (UE ID, HARQ, TFRC) SF 128, 2msec, downlink One HS-DPCCH (High Speed Dedicated Physical Control Channel) per UE in the uplink HARQ UL (ACK, NACK), CQI Other channels ADCH (Associated DCH) Set of dedicated uplink (DPCCH) and downlink (DPCH) for SRB Uplink user data can be transmitted with a DPDCH

MAC-hs:

MAC-hs MAC-hs is a new MAC protocol defined for HSDPA

MAC-hs HARQ:

MAC-hs HARQ UE can rapidly request retransmission of erroneously received data Reduced roundtrip delay and increased capacity If NACK is received Node B retransmits data UE combines the faulty block with retransmission (soft combining) MAC-hs RTT=12 ms 6 HARQ processes needed to transmit in every TTI

Power and Spectrum Utilization:

Power and Spectrum Utilization Efficient power and spectrum utilization No wasted transmission

Parameter for HSDPA::

Parameter for HSDPA: HSDPA Capability Power Margin RAB Max HS Rate Scheduling Cell Change Coverage Link Adaptation HSDPA Adm Channel Switching

hsdpaCapability:

hsdpaCapability The HSDPA capability of the cell Value : hsdpa_non_capable / hsdpa_capable RBS parameter HSDPA NON HSDPA

Power Margin:

Power Margin hsPowerMargin determining how much power can be allocated for HS-DSCH. Default value : 2 (0.2dB) Range: 2-200 Resolution: 1 Unit: 0.1dB

hsScchMaxCodePower:

hsScchMaxCodePower HS-SCCH maximum code power relative PCPICH reference power. This parameter also determines the fixed power level for HS-SCCH. UNIT=0.1(dB) RESOLUTION=5 Default: -20

HSDPA RABs:

HSDPA RABs Interactive PS 64/HS and PS 384/HS (optional) Interactive 64/HS kbps PS RAB UL: Interactive 64 kbps PS RB + 3.4 kbps SRBs on DPCH DL: Interactive PS RB on HS-DSCH + 3.4 kbps SRBs on DPCH Interactive 384/HS kbps PS RAB UL: Interactive 384 kbps PS RB + 3.4 kbps SRBs on DPCH DL: Interactive PS RB on HS-DSCH + 3.4 kbps SRBs on DPCH

RAB:

RAB allow384HsRab Switch to enable/disable the use of UL 384/HS kbps RAB in the RNC. Value : True/False RncFunction

Max HS Rate:

Max HS Rate Determine the maximum appropriate bit rate that can be used for HS-DSCH over one aggregate bit pipe over Iub. Default is 15 Unit: 0.1(Mbps) Range: 1-1000 RBS parameter

HSDPA Scheduling:

HSDPA Scheduling HSDPA scheduler is implemented in Node B Scheduler determines the UE to which data should be transmitted in the next 2 msec TTI It considers channel conditions experienced by the UE Scheduler can assign HS-DSCH to the UE with better channel quality (CQI) Short term improvements in radio conditions can mean higher throughput Each user gets the impression of being given a big data pipe

MAC-hs Scheduling:

MAC-hs Scheduling Priority queue is the same as user allocated resources in 2 msec TTI MAC-hs Scheduling determines priority queue MAC-hs functions Resource Estimation Queue Validation Queue Selection Scheduler Priority Queue 1 Priority Queue 2 Priority Queue 3 Priority Queue 4

MAC-hs Scheduling:

MAC-hs Scheduling For Queue Selection, 3 priority factors are available. f(CQI) weights downlink channel conditions. Emphasis system throughput f(delay) weights time a user has to wait for transmission. Emphasis fairness of time allocation f(average rate) weights users achievable data rate. Emphasis on fairness of throughput

MAC-hs Scheduling:

Two different algorithms available in P4 Parameter (queueSelectAlgorithm) by combination of factors Value: Round_Robin / Proporsional_Fair Round_Robin Considers only f(delay). Fairness of time allocation Proportional_Fair Combination of all the three factors Increases system throughput by prioritizing users with good quality Some fairness of time and rate allocation is also considered MAC-hs Scheduling high data rate low data rate Time #2 #1 #2 #2 #1 #1 #1 User 2 User 1 Scheduled user

Sector Throughput :

Sector Throughput GET MORE UE GET MORE UE

HS-DSCH Mobility (Cell Change):

HS-DSCH Mobility (Cell Change) HS-DSCH and HS-SCCH do not support soft/softer handover ADCH support soft/softer handover (SRB and uplink DCH) HS-DPCCH support only softer handover HS connections perform a HS cell change HS cell change performed only with cells in the Active Set. Active Set Update happens first before HS Cell Change can happen HS Cell Change cannot be performed across RNC borders The Cell Change evaluation is triggered only if the parameter hsCellChangeAllowed is set to TRUE Cell Change is performed by “RRC Physical Channel Reconfiguration”

Parameter for UE measurement Control:

Parameter for UE measurement Control hsHysteresis1d RNC Sets the Event 1D hysteresis value specific for HS connections Unit: 0.1 dB Resolution: 5 hsQualityEstimate RNC Indicates whether it is CPICH Ec/N0 or CPICH RSCP that should be used for indicating "best cell" for HS-DSCH cell selection and HS-DSCH cell change Value: CPICH_ECNO/CPICH_RSCP hsTimeToTrigger1d RNC Sets the Event 1D Time to Trigger value specific for HS connections Unit: 1 ms. Resolution: N/A

Hs Quality Estimate:

Hs Quality Estimate Default value is using RSCP

Event 1d HS:

Event 1d HS Event 1d HS is similar to event 1d Event 1d HS occurs when the signal level of a cell already included in the Active Set becomes stronger than the current best cell in the Active Set Different Hysteresis, Time to trigger and qualityestimate criteria for 1d HS

HS-DSCH Cell Change Summary:

HS-DSCH Cell Change Summary Inter RNC

HS Coverage Relation:

HS Coverage Relation Purpose of the coverage relation is to give the operator a possibility to distribute HSDPA downlink traffic among the cells of an RNC.

HS PATHLOSS THRESHOLD:

HS PATHLOSS THRESHOLD hsPathlossThreshold Maximum pathloss allowed for Serving HS-DSCH cell selection to validate the target cell for selection. Unit: 1 dB Range: 15-170 Resolution: 1 Default: 170 (max)

HSDPA Link Adaptation:

HSDPA Link Adaptation There is no power control on HS-DSCH HS-DSCH adjusts the data rate to match the instantaneous radio conditions and the available transmission power in the RBS The system adjusts the data rate by varying the effective code rate, changing the modulation scheme, and changing the number of codes Besides QPSK, the HS-DSCH can use 16QAM to provide higher data rates. ( parameter: supportOf16qam true/false) 16QAM makes more efficient use of the bandwidth than QPSK but requires greater received energy per bit. 16QAM 2 bits 4 bits QPSK

CQI Adjustment:

CQI Adjustment UE sends CQI info in the UL on HS-DPCCH to aid scheduling CQI (1-30) provides the Node B with a measure of the UE's perceived channel quality and the UE receiver performance The CQI report estimates the number of bits that can be transmitted to the UE using a certain assumed HS-PDSCH power with a block error rate of 10% UE assumes a HS- PDSCH power to calculate CQI The available HS-PDSCH power typically differs from the assumed power, and the number of codes and available modulation type may differ from the UE's assumptions, CQI is adjusted by the Node B with parameter cqiAdjustmentOn (true/false)

hsdpaUsersAdm:

hsdpaUsersAdm Admission limit for the number of users assigned to the HS-PDSCH/HS-SCCH in the cell. The limit is only applicable to RAB setup of HSDPA. Unit: 1 user Resolution: 1 Default: 10

HS-DSCH Channel Switching:

HS-DSCH Channel Switching Uplink and downlinkactivity is monitored and the algorithm requests a switch to Idle mode if no uplink or downlink activity has been detected hsdschInactivityTimer Unit: 1 s (seconds) Resolution: 1

Questions and discussion:

Questions and discussion

Slide 31:

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