pf with different hs ue cat v2[1]

7/31/2019 PF With Different HS UE Cat V2[1]

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Proportional Fair Queue Algorithm

With different HSDPA UE Categories



15/0363-FCP 101 7329 Uen Rev A Commercial in confidence Proportional Fai r Queue Scheduling with Different HS UE Category 2009-08-182

Background

The following slides explains

the different proportional fair

(High, Medium, Low) scheme testing

results performed by EMOBILE

with different HS UE categorydownloading at the same time




Analysis Scope

• The analysis focus on “Phase11” as termed by EMOBILE since at all UEs are at

the same good CQI range (25~28) and with only 1 radio link in the active set.

• The purpose is to analyse if the big difference in HS throughput with different UE

category (2 category 6 UEs and 2 category 8 UEs) is according to the flexible

scheduler implementation algorithm




Queue Selection Algorithm in P5

Scheduler strategies:

– Maximum CQI

– Proportional fair – low fairness – Proportional fair – medium fairness

– Proportional fair – high fairness

– Round-robin (P1 legacy)

– Equal rate

The different strategies will have different weightage factor added to thefunctions to give different level of fairness to users as a trade off to cellthroughput

With different selection of scheduler strategies, different queue factor in thegeneral expression is used as summarised in the next slide

C = f(CQI) x f(average rate) x f(delay) x f(retransmission) x f(air rate)

In P5, the general queue algorithm can be expressed as:




Queue Selection Contribution in

Different Strategies

Equal Rate

Round

Robin

Proportional

Fair – High

Proportional

Fair –

Medium

Proportional

Fair - LOW

Maximum

CQI

f(air rate)f(retransmission)f(average rate)f(delay)f(CQI)




Factors Affecting Proportional Fair Algorithm

f(CQI) controls the efficiency of scheduling from a system

throughput perspective by considering the downlink radio quality of each UE, by using the CQI value reported by the UE.

f(delay) considers the queuing waiting time ie. how long time each

pirority queue has not been selected by the scheduler.

f(average rate) controls the fairness of scheduling from a user

average offered throughput perspective.

f(retransmission) considers the retransmission delay ie how longtime retransmission is delayed due to not to be assigned by

scheduler after NACK is received.


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f(CQI) in field test data

Slide 16, 24 and 32 show the CQI reported by the UE during the different PF

algorithm tests. All 4 UEs measured approximately the same CQI performance

However f(CQI) further weigh the volume of data that can be transmitted basedon the CQI

Different CQI correspond to different Transport Block Size (number of bits) withdifferent UE category as shown in the next slide. The actual TBS reported fromthe measurement tool (Couei’s XCAL) is also showing similar results in slide17, 25, 33

At good CQI environment (25 and above), the ratio of Transport Block Size of Cat 8 UE and Cat 6 UE is 2 (14411/7168). This ratio is further enlarged withdifferent weightage factor from Proportion Fair High Fairness to Low Fairness.

Therefore Cat 8 UE is prioritized over Cat 6 UE in this factor in the ProportionalFair algorithm and more so in Proportional Fair Low as compared toProportional Fair High due to the weightage factor



CQI and TBS with Different UE Category



f(retransmission) in field test data

The purpose of f(retransmission) is to put retransmission data at higher

priority.

All 4 UEs regardless of UE category are having the same

retransmission rate as shown in slide 19, 27, 35 which is expected.(Note: CQIadjustmentON is not activated during data collection)

However, Cat 8 HS UE has a higher bit rate than Cat 6 UE for the

same CQI (see slide 8). With the same retransmission rate, Cat 8 HS

UE would have higher number of retransmission bits. This can also be

seen in slide 20, 28, 36 (Note: it is unclear the exact meaning of “Retransmission No” as defined byCouei due to vague explanation in the tool)

In summary: In terms of f(retransmission) Cat 8 HS UE will also be

prioritized ahead of Cat 6 HS UE



Conclusion (1)

In the Proportional Fair Algorithm, at good CQI environment Category 8 HS UE

will be scheduled ahead of Category 6 UE because of f(CQI) andf(retransmission) factor. This can be seen in slide 18, 26 and 34 by comparingthe DTX rate

When a UE is scheduled to transmit, at good CQI environment, a Cat 8 HS UEwould also result in higher throughput due to the higher code usage (see slide

14, 22, 30) compared to a Cat 6 HS UE further differentiating the throughputdifferences between a Cat 8 and a Cat 6 HS UE.

The effect is felt mainly at very good CQI environment, at a normal medium CQIenvironment (e.g. CQI=20), both UE category will be retransmitted at the sameTBS (see slide 8) so f(CQI) would not piroritise Cat 8 UE. The only difference

between would be the f(retransmission) factor.

The difference between good and medium CQI environment and differencesbetween throughput on cat 6 and cat 8 UEs can also be observed in EMOBILETesting data and also summarised in the next slide.



Good and Medium CQI Environment

Comparison with 4 UEs at the Same Position



Conclusion (2)

The HS scheduling piroritization of Cat 8 HS UE over a Cat 6 HS UE in termsof f(retransmission) can also be reduced when CQI Adjustment feature isactivated. We have observed significant improvement of NACK Rate from CQI Adjustment feature activation on September 1 on the selected GPI sites.

As a summary, – The test results performed by EMOBILE is as expected in Ericsson

feature.

– A high capability UE is prioritized over the low capability one whenthey have similar CQI value. The effect however is slightlyexaggerated in this case because CQI Adjustment Feature is notactivated and testing has been performed in extremely good CQIenvironment

– The possibility of choosing different proportional fair algorithm wouldbe suitable for operators with user using smaller data burst size. For EMOBILE, where users are mainly transferring big files, ProportionalFair – HIGH is the most optimum balancing user fairness as well ascell throughput and HSDPA channel usage efficiency



Proportional Fair - LOW



Seized PDSCH Codes ComparisonPF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



MAC-hs Throughput ComparisonPF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



UE Reported CQI ComparisonPF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



Transport Bit Size ComparisonPF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



DTX Rate ComparisonPF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



Retransmission Rate ComparisonPF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



Retransmission Number Comparison

Definition from Couei’s XCAP-W tool: Retransmission Number - Sample number to be retransmission of

thing that is transmitted in DSCH among thing, which SCCH valid is true

PF_LOW

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



Proportional Fair - MEDIUM




Seized PDSCH Codes ComparisonPF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




MAC-hs Throughput ComparisonPF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




UE Reported CQI ComparisonPF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




Transport Bit Size ComparisonPF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




DTX Rate ComparisonPF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




Retransmission Rate ComparisonPF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE







PF_Medium

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE



Proportional Fair - HIGH




Seized PDSCH Codes ComparisonPF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




MAC-hs Throughput ComparisonPF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




UE Reported CQI ComparisonPF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




Transport Bit Size ComparisonPF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




DTX Rate ComparisonPF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE




Retransmission Rate ComparisonPF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE







PF_HIGH

Cat 8 HS UE

Cat 8 HS UE

Cat 6 HS UE

Cat 6 HS UE

pf with different hs ue cat v2[1]

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