qos and rrm in 3g and beyond systems - upv conference on next generation internet design and...

12nd Conference on Next Generation Internet Design and EngineeringValència, April 3-5 2006

QoSQoS and RRM and RRM in 3G and in 3G and

Beyond Systems Beyond Systems

Oriol SallentUniversitat Politècnica de Catalunya

[email protected]


Outline

Part I: Introduction

Part II: RRM in UMTS

Part III: RRM in B3G

Part IV: Common (or Joint) RRM in a flexible spectrum scenario

Concluding remarks


Part IIntroduction


Introduction

WCDMAWCDMA

EDGEEDGE

HSDPAHSDPA

4G4G

UltrawidebandUltrawideband

RFIDRFID

BluetoothBluetooth

WIMAXWIMAX

WLANWLAN

HSUPAHSUPA

Cellular AccessCellular Access

Hot Spot AccessHot Spot Access

ProximityProximity


Introduction

• How much transmission capacity (Bandwidth) will customers require?

• How many litres of water we need for a shower?


Introduction

It is the available capacity and associated services that will condition the real use


Introduction

3 Sector base station at 25m to outdoor PC card

100kb/s 1.49km

1Mb/s 0.78km

10Mb/s 0.41km

100Mb/s 0.21km

Data Rate Site density

1

3.6

15

50

Range


Introduction

500$ per Mbyte

SMS2$ per Mbyte

Voice on mobile0.1$ per Mbyte

Voice on Fixed

0.001 per MbyteTelevision

The cost of a service is related to the network complexity needed to deliver it, ...but its price must be related to the value human eyesput on it.


Introduction

Mobile systems integration

NetworksService enablers Operator DevicesContent Consumer

http://www.orange.com/default.asp?UID=&UAT=


Introduction

Fixed-mobile convergence

Very different approaches…• Mobile guys standardise then do!• Fixed guys do then standardise!

Users need a truly mobile solution….


Introduction

The problem faced by a network operator is to offer a system where the number of users is maximized for a given set of QoS requirements. In this problem two aspects can be clearly distinguished:

• Network planning (e.g. the design of the fixed network infrastructure in terms of number of cell sites, cell site location, number and architecture of concentration nodes, etc.)

• Radio resource allocation (e.g. for a given network deployment,the way in which radio resources are dynamically managed in order to meet the instantaneous demand of the users moving around the network)


Introduction

RRU (Radio Resource Unit): Set of basic physical transmission parameters necessary to support a signal waveform transporting end user information corresponding to a reference service.

RRU in FDMA: a certain bandwidth within a given carrier frequency RRU in TDMA: a pair of a carrier frequency and a time slotRRU in CDMA: a carrier frequency, a code sequence and a power level

RADIONETWORKPLANNING

RADIONETWORK

DEPLOYMENT

RADIONETWORK

OPERATION

RRU provision along timeand space

RRU allocation

RRM / CRRM

• Other physical transmission elements: modulation scheme, channel coding scheme, etc…• Multi-service scenario different services demand different amount of RRU


Introduction

GERAN UTRA WLANt t t

f

c

RRM-GERAN RRM-UTRAN RRM-WLAN

GERAN UTRA WLANt t t

f

c

CRRM


Introduction

GERAN RADIO RESOURCESUTRAN RADIO RESOURCESWLAN RADIO RESOURCES

AMOUNT OFCOMMON

RADIORESOURCES


RRM in UMTS

• Radio Resource Management is a complex problem affected by manydifferent issues, with crossed effects among the different parameters of a given RRM strategy as well as among the different RRM strategies themselves.

• Changes in the scenario or system conditions may lead to different RRM suitable solutions.

• A step by step approach seems to be required…..

… let start with a single dimension (e.g. RRM in UMTS) and then move toadditional dimensions (i.e. heterogeneous RANs)


Part IIRadio Resource Management

in UMTS


RRM in UMTS

Node B

IuIur

Iub

Node B

Node B

Node B

RNCVLR HLR

GSN+

MSC+

UTRAN

PCM

ATM/ AAL2

IP/ GTP

RNC

Packed Service CN =GPRS +

Connection Service CN

UMTS Core Network


RRM in UMTS

• Radio Resource Management: Set of algorithms devoted to achievean optimal usage of the radio interface, to guarantee a certain target QoS, to maintain the planned coverage area and to offer a high capacity.

• RRM is strongly related to QoS concept.

• QoS can be seen at different levels:

• System accessibility (call blocking)

• Subjective perceived quality

• Delay, rate, reliability


RRM in UMTS

• RRM strategies will definitively play an important role in a mature UMTS scenario

• RRM functions can be implemented in many different ways

Impact on the overall system efficiency and on the operator infrastructure cost

• RRM strategies are not subject of standardisation

Differentiation issue


RRM in UMTS

UMTS

W-CDMAFLEXIBILITY

KEYDESIGN

PRINCIPLE

RRMIS THE

ENABLER

The benefits deriving from flexibility justify the research efforts for smart radio resource management algorithms development. By doing so, the potentials of technological advances (e.g. UMTS) can be fully exploited.


Radio Resource Management in UMTS

RRM strategies:

• Power control (PC)• Handover (HO)• Admission control (AC)• Load control (LC)• Packet Scheduling (PS)

BS

} Connection level

} Network level

RNC

PCPC PC HO

LC LC AC

PS


RRM in UMTS: Admission control

• The admission control procedure is used to decide whether to accept or reject a new connection depending on the interference it adds to the existing connections. Therefore, it is responsible for deciding whether a new RAB (Radio Access Bearer) can be set-up and which is its allowed TFCS (so that the maximum allowed bit rate is determined).

• Both uplink and downlink must be considered in a consistent way.



Interferencelevel

Imax

Iaver

I(t)

t

Interferencelevel

ImaxIaver

I(t)

t



• Admission control principles make use of the load factorload factor and the estimate of the load increase that the establishment of the bearer request would cause in the radio network:

Uplink caseUplink case:

Notherown

NUL PPP

P++

−=1η

• As the load factor approaches unity, the power demand tends to the infinity, so it is necessary to limit it somehow

maxηηη ≤∆+UL

Admission control algorithm:

ACCEPT IF Need to be estimatedULηη∆ }



0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

110

111

112

112

113

114

115

116

116

117

118

119

119

120

121

122

123

123

124

125

126

126

Tiempo (s)

Fact

or d

e ca

rga

Load factor evolution in a cellularscenario, mobiles at 50 Km/h

0

0,2

0,4

0,6

0,8

1

110

111

112

112

113

114

115

116

116

117

118

119

119

120

121

122

123

123

124

125

126

126

Tiempo (s)

Fact

or d

e ca

rga

Load factor evolution in a cellularscenario, mobiles static



Downlink caseDownlink case:

• It may seem more reasonable to control the downlink operation through the transmitted power rather than through the cell load factor, as it uses to be the case in the uplink.

• The considered admission control algorithm checks the followingcondition to decide the acceptance of a new connection request in the system, arriving at the i-th frame:

)()()( * iPiPiP TTAV ≤∆+T

jiPiP

T

jT

AV

∑=

−= 1

)()(

PT(i-j): Node-B transmitted power at (i-j)-th framePT*(i): Admission threshold at i-th framePAV(i): Average transmitted power during the last T frames

: Power increase estimation due to the new request )(iPT∆



30

32

34

36

38

40

42

44

110

112

113

114

115

116

118

119

120

121

122

124

125

126

127

128

130

131

132

Tiempo (s)

Pote

ncia

tran

smiti

da N

odo

B (d

Bm

)

30

32

34

36

38

40

42

44

110

112

113

114

115

116

118

119

120

121

122

124

125

126

127

128

130

131

132

Tiempo (s)

Pot

enci

a tra

nsm

itida

Nod

o B

(dBm

)

Node B transmitted power evolutionin a cellular scenario, mobiles at 50 Km/h(pilot: 30 dBm)

Node B transmitted power evolutionin a cellular scenario, mobiles static(pilot: 30 dBm)


RRM in UMTS: Congestion control

CDUL ηη >

Congestion control : It faces situations in which the system has reached a congestion status and therefore the QoS guarantees are at risk due to the evolution of system dynamics (mobility aspects, increase in interference, etc.).

Three components:• Congestion detection• Congestion resolution• Congestion recovery

Detection criterion:in at least 90% of the frames within ∆TCD



The congestion resolution algorithm executes a set of rules to lead the system out of the congestion status. A lot of possibilities exist to carry out this procedure. In any case, three steps are identified:

a) Prioritisation: Ordering the different users from lower to higher priority. b) Load reduction: Reducing the TFCS (i.e. limiting the maximum transmission rate) for a certain number of users, beginning from the top of the prioritization table. c) Load check: After the actions taken in b), one would check again the conditions that triggered the congestion status. If congestion persists, one would go back to b) for the following group of users in the prioritization table.



Interferencelevel

I(t)

I’(t)Imax

t


RRM in UMTS: Short term RRM

Short term RRM (i.e. 10 ms timeShort term RRM (i.e. 10 ms time--scale):scale):

Interferencelevel

I(t)

I’(t)Imax

t


Part IIIRadio Resource Management

in B-3G


RRM in B3G

The heterogeneous network concept is intended to propose a flexible and open architecture for a large variety of wireless access technologies, applications and services with different QoS demands, as well as different protocol stacks.

Radio access networks include cellular networks and also otherpublic non-cellular access networks (e.g. WLAN).

Cellular networks may in turn be subdivided into different layers(e.g. macro, micro or picocells).

In these new scenarios, different Radio Access Technologies (RATs) will coexist and will operate in a coordinated way.


RRM in B3G

Wireless networks differ from each other by air interface technology, cell-size, services, price, access, coverage and ownership.

The complementary characteristics offered by the different radio access technologies (RATs) make possible to exploit the trunkinggain leading to a higher overall performance than the aggregatedperformances of the stand-alone networks.

Clearly, this potential gain of B3G systems can only turn into realityby means of a proper management of the available radio resources.

Common Radio Resource Management (CRRM) refers to the set offunctions that are devoted to ensure an efficient and coordinated use of the available radio resources in heterogeneous networks scenarios


RRM in B3G

Coverage/Mobility

Bit rate

WLAN

UMTS

GSM

Coverage/Mobility

Bit rate

WLAN

UMTS

GSM

Coverage/Mobility

Bit rate

WLAN

UMTS

GSM

B3G

B3G

Coverage/Mobility

Bit rate

WLAN

UMTS

GSM

B3G

B3G


RRM in B3G


RRM in B3G: EVEREST QoS Architecture

WQB BB

MPDF

Policy-based QoS Management

Policy Repository

ExternalDomains SLS NegotiationSession

Establishment

ServiceSupportDomain

(e.g. IMS)

MMT

ResourceActivation(ie. PDP Contextsignalling)

End-to-End Session Establishment Signalling (e.g. SIP/SDP)

RNCRAN (UTRAN)

RAN(GERAN)

RAN (TightCoupled WLAN)

Diffserv IP CoreNetwork

IuGTP Micromobility

Iu or GbBSC

APC

SGSN

SGSN

GGSN

Iu or Gb

ExternalQoS Domain


RRM in B3G

Two types of entities are considered for the management of the radio resource pool in the 3GPP:

• The RRM entity, which carries out the management of the resources in one radio resource pool of a certain radio access network.

• The CRRM entity, which is involved in the coordinated management of the resource pools under different RRM entities.

CRRM entity

CRRM entity

RRM entity

RRM entity

RRM entity

RRM entity

- Information reporting

- Information reporting - RRM decision support

- Information reporting - RRM decision support


RRM in B3G

The interactions between RRM and CRRM entities involve mainly two types offunctions:

1) Information reporting function

- Dynamic measurements (e.g. the current load, the transmitted carrier power, etc.)

- Static information on cells (e.g. if they are overlapped or if they belong to different HCS layers, whether a cell supports GPRS, EDGE, etc.)

2) RRM decision support function (how the CRRM and RRM entities interact for taking decisions)

The CRRM entity may be implemented either into Existing nodes Existing nodes or in Separate Separate nodesnodes


RRM in B3G

RRM functionalities in a single-RAT context:• Admission control• Congestion control• Horizontal (intra-system) handover• Packet scheduling• Power control

When these functionalities are coordinated between different RATs in a heterogeneous scenario, they can be denoted as “common” (i.e. thus having the common admission control, common congestion control, etc.)

In an heterogeneous scenario two specific additional functionalities arise:• Initial RAT selection• Vertical (inter-system) handover


Algorithms & Results

Service-based policy

VG (Voice GERAN) policy: Voice service is allocated to GERANInteractive service is allocated to UTRAN

VU (Voice UTRAN) policy: Voice service is allocated to UTRAN Interactive service is allocated to GERAN

VU VG VG (no TrCH switch)

UL DL UL DL UL DL

www users

0.5 km

1 km

0.5 km

1 km

0.5 km

1 km

0.5 km

1 km

0.5 km

1 km

0.5 km

1 km

200 2.18 2.08 2.22 2.17 2.14 2.14 2.20 2.22 2.03 2.01 2.08 2.07

600 3.01 2.88 3.15 3.09 2.96 2.95 3.16 3.15 2.06 2.05 2.11 2.11

1000 3.80 3.64 4.05 3.96 3.77 3.76 4.08 4.08 2.08 2.05 2.14 2.13

400 voice

Aggregated throughput (Mb/s)



Service-based policy

VU VG

UL DL UL DL

www users

0.5km

1km

0.5km

1km

0.5km

1km

0.5km

1km

200 2.91 3.09 0.74 0.76 2.89 2.88 0.76 0.76

600 2.94 3.15 0.77 0.83 2.90 2.90 0.76 0.76

1000 3.03 3.74 0.99 1.26 2.91 2.93 0.76 0.77

400 voice

Average packet delay (s)

• VU more sensitive to cell range increase• VU more sensitive to load increase (i.e. packet delay increases)

It seems more suitable to map voice to GERAN and www to UTRAN



Radio network-based policy

Indoor traffic is allocated to GERAN Better utilisation of the radioresources

0

1

2

3

4

5

6

7

8

9

10

0 200 400 600 800 1000

Voice users

Dro

ppin

g pr

obab

ility

(%)

Random policy

Indoor policy



Load balancing

Conversational – Business

UTRAN GERAN WLAN

Interactive – BusinessConversational – ConsumerInteractive – Consumer

Extension to: Indoor/outdoor, Pedestrian/car, etc.



Network-controlled cell breathing

RT

RC1

co-site cells

FDMA/TDMA coverage area

CDMA coverage area

RC2

1.5

2

2.5

3

3.5

4

4.5

5

400 500 600 700 800 900 1000 1100 1200

Users

Agg

rega

ted

thro

ughp

ut (M

b/s)

NCCB LB



CRRM algorithms should consider multi-mode terminal capabilities

UL Throughput degradation Average UL packet delay for interactive users in GERAN

0

5

10

15

20

25

75 50 25Multi-mode Terminal Availability (%)

Ave

rage

Pac

ket D

elay

(s)

VU=400;WU=400

VU=200;WU=200

0

5

10

15

20

25

30

35

100 75 50 25Multi-mode Terminal Availability (%)

Thro

ughp

ut D

egra

datio

n (%

)

VU=600;WU=600

VU=400;WU=400

VU=200;WU=200

• Increase of degradation with decrease of multi-mode availability

• Increase of degradation with increase of number of users

• Impact on the interactive users exhibiting higher delays



Average Packet Delay improvement with dedicated slots

0

0.5

1

1.5

2

2.5

3

75 50 25

Multi-mode Terminal Availability (%)

Ave

rage

Pac

ket D

elay

(s)

VU=400;WU=400

VU=200;WU=200

• Interactive users benefit from the reservation scheme exhibiting lower packet delays.


Part IVCommon (or Joint) Radio Resource

Management in a flexiblespectrum scenario


JRRM & ASM

Fixed spectrum assignments lead to ineficient spectrum utilisation

New regulation regarding spectrum management is needed


JRRM & ASM

COGNITIVE RADIO : A RADIO OR SYSTEM THAT SENSES AND IS AWARE OF

ITS OPERATIONAL ENVIRONMENT AND CAN DYNAMICALLY,

AUTONOMOUSLY AND INTELLIGENTLY ADJUST ITS RADIO OPERATING

PARAMETERS (AWARE+ADAPTIVE+LEARNING)

• Sensing over wide frequency band

• Identifying both other users of that band as well as the transmission opportunities

• Coordinating the actual use of the radio band by communicating with other devices

A cognitive radio is a software radio equipped with sensors and software that allow it to

perceive the operating environment and learn from experience


JRRM & ASM

JOINTRRM

LOCALRRM #1

…...

...

LOCALRRM #n

SM

DNPM

Radio-dependent part ofheterogeneous reconfigurable networks

ReconfigurableUE

HOURS

HOURS

MINUTES/SECONDS

MINUTES/SECONDS

SECONDS/MILISECONDS

SECONDS/MILISECONDS

HOURS/MINUTES

DecisionsFeedback / Measurements


Concluding remarks


Concluding remarks

• The heterogeneous network concept is intended to propose a flexible and open architecture for a large variety of wireless access technologies, applications and services with different QoS demands, as well as different protocol stacks.

• Common (or Joint) Radio Resource Management (CRRM or JRRM) refers to theset of functions that are devoted to ensure an efficient and coordinated use of the available radio resources in heterogeneous networks scenarios

• B-3G opens a new dimension in the RRM problem

• The concept, functional model, split of functionalities between RRM and CRRMentities have been discussed


Concluding remarks

• Some algorithms have been presented and supported with simulation results:• Service-based initial RAT selection• Radio network-based initial RAT selection• Load balancing-based initial RAT selection• Network controlled cell breathing

• The role of terminal’s multimode/reconfigurable capabilities has been emphasized

• Interactions between JRRM and ASM have been detailed

qos and rrm in 3g and beyond systems - upv conference on next generation internet design and...

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