signaling load evaluations for policy-driven cognitive management architectures

Signaling load evaluations for policy-driven cognitive

management architectures

Kostas TsagkarisM. Akezidou, A. Galani, P. Demestichas

Telecommunication Networks & Integrated Services LabDept of Digital Systems, University of Piraeus,

Piraeus, Greece

Wireless Track – Session #2 BROADNETS 201027 October 2010 October 25-27, Athens, Greece

Dr. Kostas TsagkarisWireless Track – Session #2 BROADNETS 201027 October 2010 October 25-27, Athens, Greece

Outline

Motivation, problem area

Overview of considered cognitive management architecture

Signaling load evaluation methodology

Application to an indicative scenario

Test cases and results

Conclusions and future work

Dr. Kostas Tsagkaris

Outline











Significant increase in user demands, mainly stemming from the wireless and mobile domains

Heterogeneous wireless networks with great levels of complexity Multiple, collaborating Radio

Access Networks (RANs) Able at operating a plethora

of diverse Radio Access Technologies (RATs)

Variant types of Mobile Terminals (MTs), with the ability to choose among various supported RAN/RATs

Both devices and networks with dynamic spectrum access capabilities

(Cognitive) (Cognitive) Access PointAccess Point

(Cognitive) (Cognitive) Base StationBase Station

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How to optimally select and use spectrum and radio resources?

Stress for developing mechanisms to confront the challenges and to leverage the opportunities posed by such a versatile radio environment.

Solution: adaptive and flexible management paradigms that are able to dynamically manage network elements and terminals, ensuring the great availability and efficient usage of spectrum and other radio resources

(Cognitive) (Cognitive) Access PointAccess Point

(Cognitive) (Cognitive) Base StationBase Station

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RAT?spectrum?frequency? radio resources?…

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RAT?spectrum?frequency? radio resources?…

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Motivation, problem area (cont.)

A Policy-driven Cognitive Management Architecture is proposed as a solution to the above problems– destined to the optimized management of future wireless networks

operating in versatile radio environments– comprises a generic amalgamation of a set of architectures that

have been proposed for managing future networks A variant structure of the Functional Architecture (FA) that has

been developed by the E3 European project– for introducing reconfigurable, cognitive Systems in the B3G world– for improving the utilization of spectrum and radio resources

More importantly, a variant of the architecture that has been actually elaborated within the Working Group 3 (WG3) of the ETSI Reconfigurable Radio Systems Technical Committee (ETSI RRS TC)– In May 2009, the ETSI Board has approved the respective technical

report as ETSI TR 102.682 “Functional Architecture (FA) for the Management and Control of Reconfigurable Radio Systems”



Motivation, problem area (cont.)

However… little work on the performance assessment of the above cognitive management architectures so far

This work places focus on the evaluation of signaling loads that the cognitive management architecture will burden to the network that it operates in



Outline










DSM: – assigns operating

frequencies to RATs – detects opportunities for

sharing or trading spectrum with other network operators (NOs)

DSNPM:– manages and reconfigures

the network elements– detects the new elements– provide the essential

configuration information of the managed RATs to MTs

– derivates policies for the managed MTs

– calculates metrics on spectrum utilization

CCM:– implements the

decisions of DSNPM and JRRM in network elements and JRRM in MTs

– responsible for all the stages of reconfiguration and all the possible related actions (e.g. SW downloads)

JRRM:– is responsible

for jointly managing the radio resources belonging to heterogeneous RATs

– performs functionalities such as MT access selection, neighborhood information provision, and QoS/bandwidth allocation/admission control

Functional entities and interfaces

RAT:– Encapsulates the set of network

and/or terminal elements and resources that are bound to a specific radio access technology and are subject to reconfiguration


Outline









Our purpose is to calculate the signaling loads in the interfaces of the architecture– Assuming mapping of the functional interfaces to actual system

interfaces e.g. ones defined in 3GPP The interfaces are first defined in terms of elementary

procedures Every single operation/scenario in the considered

architecture is supposed to be built from a set of elementary procedures taking place in the interfaces of the architecture (thus the term “elementary”)

Calculations can be then done by characterizing the signaling loads that are needed to carry out this set of elementary procedures



Signaling load evaluation methodology (cont.)

1. Determination of procedures in the considered scenario(s): Every scenario in question can be seen as a constitution built from a set of elementary procedures taking place in the interfaces of the architecture.

2. Determination of messages: Determination of messages that flow in-between the peer entities of the interfaces and are used to carry out the procedures

3. Determination of parameters: Determination of the set of parameters needed to be conveyed within each of the messages defined in the previous step

4. Message length calculation: Calculation of the length of every message considered as deriving from the summation of its constituent parameters’ length values.



Outline









Application of the above defined methodology to an indicative scenario, namely “New Spectrum Assignment”:– New frequencies are disposed by a regulator to a

network operator (NO)– The NO want to operate the new frequencies for

specific Radio Access Technologies (RATs)– The scenario includes processes and exchange of

messages that are necessary for informing about and accommodating the new spectrum to the network (network elements and terminals)



1. Determination of procedures

10 procedures in total



2. Determination of messages (cont.)


10 procedures in total 15 messages



1. DSM first requests updated spectrum utilization metrics from DSNPM (msg:SpectrumUsageRequest)

2. DSNPM then requests from n-JRRM, updated context information (msg:ContextInfoRequest_MJ)

3. n-JRRM forwards the context information related requests to the respective entities in MTs, namely m-JRRMs, as well (msg: ContextInfoRequest_JJ-TN)

4. The context information is sent from MTs to n-JRRM (msg: ContextInfoResponse_JJ-TN)

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3


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5. n-JRRM requests from RATs, context and current configuration information, as well (msg: Context&ConfigurationInfoRequest)

6. This context & configuration information is sent to n-JRRM (msg:Context&ConfigurationInfoResponse)

7. The total information is forwarded to DSNPM (msg: ContextInfoResponse_MJ)

8. Based on this information DSNPM calculates the current spectrum usage metrics and forwards them to DSM (msg: SpectrumUsageResponse)

9. DSM implements algorithms that result to the new spectrum assignment and sends the new directives for final allocation of the frequencies to DSNPM (msg:SpectrumAssignmentRequest)

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10. DSNPM decides for the final allocation of frequencies and informs a number of RATs (n-CCM) for reconfiguration (msg: ReconfigurationRequest_MC)

11. n-CCM entities determine the specific moment of reconfiguration by forwarding the DSNPM’s information to the RATs (msg: ReconfigurationRequest_CR) and implement the reconfiguration process

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12. n-CCM supervises the reconfiguration process and when it is informed by RATs for the successful process’s effectuation (msg: ReconfigurationResponse),

13. it informs DSNPM (msg: ReconfigurationExecutionNotification)

14. DSNPM sets out a context notification procedure in order to inform MTs for the updated context information in the network (msg: NetworkContextNotification)

15. Finally, DSNPM derives new policies and sends them to MTs via n-JRRM (msg: Policy) 13

14

15

12



3. Determination of parameters

Next step: describe the type and number of parameters that each of the messages must convey for satisfying the purpose for which the architecture has been designed for i.e. spectrum and radio resource usage optimization

Mainly based on the authors’ view and experience, albeit in alignment with the respective functionality in each of the functional entities

Consider msg: ContextInfoResponse_JJ-TN as an example. It may comprise information such as: – MT identification number– Reconfiguration capability– Current configuration of its interfaces– Geographic coordinates at a time instance– Mobility profile– Requested services– Signal measurements – …etc


4


4. Message length calculation

A more formal description of the parameters and accordingly of the messages and procedures seems to be of prominent importance

Use of Abstract Syntax Notation One (ASN.1) in order to describe the syntax of the messages conveyed between the interfaces of the architecture in a formal way– ASN.1 is a standardised specification language that describes data

structures for representing, encoding, transmitting, and decoding data

Calculation of the length of every message as a summation of its constituent parameters’ length values

Calculations are done on top of and independently of any specific transport protocol



4. Message length calculation (cont.)

Procedure

Message

Interface

Calculated Load assuming

BER encoding

Calculated Load w/o encoding


Parameters



Interesting note 1: The evaluation work reveals

that the loads obey some generic formulas comprising a combination of both variable and constant parts

The variable part reveals dependency on parameters, which – are specific to each procedure

e.g. number of requested frequency bands f

– or more generic ones e.g. such as the number of mobile terminals m (like in ContextInfoResponse_JJ-TN)




Interesting note 2: One of the most interesting contributions of this work is the formalization of

the Policy message Policies are derived by the network (a policy derivation function in DSNPM)

and are communicated to the user mobile terminals for guiding their selection of proper radio resources (radio resource selection policies)

Policies are formatted (using ASN.1) so that they apply to the whole set (broadcast-like) or a sub-set (multicast-like) of MTs.

They are formatted as rules adhering to the well known Event-Condition-Action (ECA) type

ON <Event> IF <Condition> THEN <Action>

– the event part specifies the signal that triggers the invocation of the rule (e.g. changes in spectrum)

– the condition part is a logical test that if evaluates to true (e.g. MTs located at specific areas and use specific type of service), causes the action to be carried out,

– the action part consists of the actual execution of the modification/update (e.g. change operating RAT/freq etc.)

Calculation of the Policy message length by applying the same methodology



Outline









Test case 1: Generic evaluations– Process of evaluations of the signaling load by assuming a

generic situation


Number of active mobile terminals 50

Number of Flexible Base Stations (FBSs) 3

Number of RATs 2

Total produced signaling load (in bytes) Air and core signaling loads (in bytes)

Signaling load (in bytes) per procedure Signaling load (in bytes) per interface


Test cases and results (cont.)

Test case 2: Scalability issues– How the signaling load evolves in function to the number of

RATs, of FBSs and of MTs in the managed network?


Evolution of signaling load vs number of MTs

Evolution of signaling load vs number of FBSs

Evolution of signaling load vs number of RATs


Test cases and results (cont.)


Test case 3: Signaling delays– The objective is to give some evidence on the delay that the management

operations will suffer as a result of the transmission of the produced management signaling information

– Assumed wired and wireless links offering 100Mbps and 70Mbps of capacity, respectively (i.e. S1-MME and air interfaces in 3GPP LTE)

Evolution of signaling delay vs number of FBSs Evolution of signaling delay (in ms) vs number of RATs

Evolution of signaling delay vs number of MTs


Outline









Conclusions The heterogeneity and versatility of future wireless networks resulted in a

cognitive management architecture for offering optimized management A methodology for evaluating signaling loads in this management

architecture was presented Results that were obtained from the application of the methodology to an

indicative scenario were presented and showed that the management architecture will not aggravate the overall network operation

Future work Handling the complete set of scenarios Identification of the periodicity of specific procedures-messages in order to

give insight on the expected load that will regularly appear in the managed network (already done)

Mapping to existing transport protocols that currently used for signaling purposes

Setup an experimentation platform for validating the proposed methodology – already done based on Java Agents DEvelopment (JADE) framework


Further reading

K.Tsagkaris, M.Akezidou, A.Galani, P.Demestichas, “Evaluation of Signalling Loads in a Cognitive Network Management Architecture”, submitted, available under request

A.Galani, K.Tsagkaris, P.Demestichas, “Information Flow for Optimized Management of Spectrum and Radio Resources in Cognitive B3G wireless networks”, Journal of Network and Systems Management, Springer, Vol. 18, Issue 2, pp. 125-149, June 2010

A.Galani, K.Tsagkaris, N.Koutsouris, P.Demestichas, “Design and Assessment of Functional Architecture for Optimized Spectrum and Radio Resource Management in Heterogeneous Wireless Networks”, International Journal of Network Management, Wiley, to appear

K.Tsagkaris, N.Koutsouris, A.Galani, P.Demestichas, “Performance Assessment of a Spectrum and Radio Resource Management Architecture for Heterogeneous Wireless Networks”, in Proc. Future Network & Mobile Summit 2010, Florence, Italy, 16th -18th June 2010

K.Nolte, A.Kaloxylos, K.Tsagkaris et al. “The E3 architecture: Enabling future cellular networks with cognitive and self-x capabilities”, International Journal of Network Management, Wiley, to appear

G.Dimitrakopoulos, P.Demestichas, A.Saatsakis, K.Tsagkaris, A.Galani, J.Gebert, K.Nolte, “Functional Architecture for the Management and Control of Reconfigurable Radio Systems”, Vehicular Technology Magazine, IEEE, vol.4, no.1, pp.42-48, March 2009

ETSI TR 102.682 “Reconfigurable Radio Systems (RRS); Functional Architecture (FA) for the Management and Control of Reconfigurable Radio Systems”, V1.1.1 (2009-07)


Acknowledgment

This work was performed in the project E³ (www.ict-e3.eu) which has received research

funding from the Community's Seventh Framework programme. The work is evolved in the context of UniverSelf and OneFIT (www.ict-onefit.eu <http://www.ict-onefit.eu/>) Projects. This paper reflects only the authors' views and

the Community is not liable for any use that may be made of the information contained therein.


Thank you……

Questions?

Contact details:Dr. Kostas TsagkarisUniversity of Piraeus

Department of Digital SystemsE-mail: [email protected]

signaling load evaluations for policy-driven cognitive management architectures

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