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7.2.2 Assumptions
a. The call flows presented are based on using the ITU-T H.323 protocol between the Mobile Station (MS) and the Gatekeeper. b. The gatekeeper and the IPSSF have been co-located in order to avoid any showing information flows between the two entities. Standardisation of the information flows between these entities is fo...
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7.2.3 Functional Architecture
The proposed functional architecture is discussed in [6] and is shown in Figure 6. The main idea behind this functional architecture is to be able to reuse existing (circuit switched) CAMEL services for VoIP. Figure 6: Proposed functional architecture
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7.3 Message Flows
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7.3.1 Registration
It is not within the scope of this feasibility study to investigate or select the registration and location update process that must exist within a multimedia service network. However this section outlines a possible registration process that allows CAMEL Subscriber Information (CSI) to be stored in the Gatekeeper/IPSS...
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7.3.2 MO call requiring CAMEL interaction
The call flows for a mobile originated (MO) calls are shown in Figure 8 and are further explained below: {1} The MS wishes to place a VoIP call. A PDP context must be established to allow an IP session to be set up. {2} The MS checks that it is allowed to place a call via RAS Admission Request message. {3} If the MS is...
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7.3.3 MT call requiring CAMEL interaction
The call flows for mobile terminated (MT) calls are shown in Figure 9 and are further explained below: {1} An incoming H225 Setup message is received by the mediation gatekeeper in the home network of the called subscriber. (The incoming call could be from an other H.323 gatekeeper or H.323 signalling gateway represent...
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7.4 State Models
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7.4.1 H.323 and CAMEL O-BCSM
Figures 10, 11 and 12 show the relationship between the H.323 protocol state model and the points in call (PICs) defined in the CAMEL phase 3 Originating Basic Call State Model (O-BCSM) for successful and unsuccessful call attempts. The O-BCSM represented is based on CAMEL phase 3 state models as described in reference...
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7.4.2 Successful call establishment
Figure 10 shows the PICs and relationship to H.323 messages for a successful call establishment of MO call with CAMEL interaction. {1} The H.225 Setup message indicates that a dialled number is received from the MS and detects that an O-CSI exists for this subscriber. {2} Analysis of the O-CSI takes place and gsmSCF is...
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7.4.3 Unsuccessful call establishment due to gatekeeper admission reject
Figure 11 shows the PICs and relationship to H.323 messages for the situation where the destination is refused permission to accept the incoming call by the gatekeeper. An AdmissionReject message may be sent by the gatekeeper to the destination is registered with for reasons specified in RAS procedures. In order to kee...
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7.4.4 Unsuccessful call establishment due to refusal by destination party
Figure 12 shows the PICs and relationship to H.323 messages for the situation where the destination does not accept the incoming call request. Once again, in order to keep the Figures relatively simple, the PICs O_Null&Authorise.. and Analyse_Info and corresponding message flows are not shown. {1} Instructions received...
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7.4.5 H.323 and CAMEL T-BCSM
Figures 13 and 14 show the relationship between the H.323 protocol state model and the points in call (PICs) defined in the CAMEL phase 3 Terminating Basic Call State Model (T-BCSM) for successful and unsuccessful MT call attempts. The T-BCSM represented is based on CAMEL phase 3 state models as described in reference ...
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7.4.6 Successful MT call delivery
Figure 13 shows the PICS and relationship to the H.323 protocol state model for a successfully established MT call requiring CAMEL interaction. {1} The H.225 Setup message arrives at the gatekeeper the destination MS is register with. If a T-CSI exists for the subscriber, a T-BCSM instance is created. {2} Analysis of t...
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7.4.7 Unsuccessful MT call delivery
Figure 14 shows the PICs and relationship to H.323 message for the situation where the terminating MS does not accept the incoming call. {1} The H.225 Setup message arrives at the gatekeeper the destination MS is register with. If a T-CSI exists for the subscriber, a T-BCSM instance is created. {2} Analysis of the T-CS...
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7.5 CAMEL Integration
Integration of CAMEL functions with H.323 Gatekeeper functions may require enhancements to H.323 standards or CAMEL standards. Some initial work has been done to identify the standards that may need to be enhanced and to assess the extent of the changes required.
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7.5.1 Impact on H.323 Standards
Section 7.4 describes and illustrates how H.225 messages may be mapped to O_BCSM and T_BCSM Detection Points (DPs) at the Gatekeeper/SSF. When studying the Figures it can be seen that some CAMEL Phase 3 DPs (such as O_Active) have good correspondence with H.225 messages at the Gatekeeper, while other DPs require more d...
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7.5.2 Impact on CAMEL and other UMTS Standards
It is likely the some functional modelling additions and some CAP message information element additions will be needed. It is also likely that some HLR/VLR data and MAP protocol additions may be needed. It is of course very difficult to assess and describe exactly how much effort and meeting time is required to effect ...
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7.6 Service Impacts
The combination of CAMEL and H.323 (as described in this report) may support some GSM supplementary services, such as unconditional call forwarding (subject to some re-engineering) and perhaps most operator specific services (depends on the extent of any reduced functionality necessary for integration). Every service n...
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7.7 Multimedia Evolution
The proposal in this report is focused on voice not multimedia. Control of multimedia services requires further study. However, the proposal does not in any way preclude CAMEL evolution to control multimedia services supported by the H.323 family of recommendations. It is likely that further enhancements to the protoco...
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7.8 Advantages
The following advantages have been identified:  Maximises the re-use of existing functional entities, protocols and services. Such reuse decreases the development and ownership costs allowing existing familiar 2G services to be provided to 3G subscribers at an early stage.  Minimum changes to the CSE for the support ...
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7.9 Disadvantages
The following disadvantages have been identified:  Introduces new functional entity ‘IPSSF’, which provides the necessary mapping between the Gatekeeper and the CSE. However, this functional entity is based on the functions already provided by a VMSC/GMSC, where already standardised process such as the gsmSSF can be ...
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8 SIP Solution
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8.1 Description
The IETF Multiparty Multimedia Session Control (MMUSIC) working group specifies an IP telephony architecture (Figure 15). The architecture is seen as an alternative to ITU-T H.323 family of recommendations that is simpler to implement. It allows for the possibility of interworking with H.323 terminals. However, H.323...
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8.2 Architecture
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8.2.1 Introduction
This section of the report provides information flows that illustrate the possible interaction of CAMEL and SIP. In particular it provides a proposal for the triggering of CAMEL services as well as a mapping between the CAMEL call states and the call states of the Session Initiation Protocol (SIP). An overall objective...
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8.2.2 Functional Architecture
The proposed functional architecture is derived from various companion contributions relating to the technical report. It is provided here for completeness. The concept of the ‘IPSSF’ is introduced which acts as an overlay between the IP telephony call control and the Intelligent Network layer provided by the CAMEL Ser...
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8.2.3 Basic concept of the proposal
Subscribers may register in the visited SIP network allowing the subscriber to receive incoming calls. A subscriber may use the MSISDN as an additional identifier in the registration process. Upon registration with the server, the CAMEL subscription information for the subscriber is sent to the IPSSF by the HLR in the ...
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8.2.4 Assumptions
a. All the call flows show that the SIP Proxy Server and the IPSSF have been co-located in order to avoid showing an information flows between the two entities. Standardisation of the messages for this interface is for further study. b. The attach/detach and establishment of the Packet Data Protocol (PDP) session are b...
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8.3 Message Flows
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8.3.1 Proposed Registration process
This section outlines a possible registration process based on the SIP REGISTER method, which allows CAMEL subscription information to be stored in the SIP Proxy Server/IPSSF. IETF RFC 2543 [4] defines the term Registrar for registration purposes and it is the SIP registrar that accepts the REGISTER method. In this sec...
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8.3.2 Mobile Originating Call with CAMEL interaction
This section deals with the mobile originating calls that require interaction with CAMEL. The call flows are shown in Figure 22 and are further explained below: {1} The MS wishes to place a VoIP call. A PDP context is established to allow an IP session to be established over the GPRS network. {2} The User Agent Server ...
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8.3.3 Mobile Terminating Call with CAMEL interaction
This section deals with the CAMEL interaction for mobile terminated calls. A CAMEL service is triggered if the triggering criteria held in the called subscriber’s T-CSI matches the characteristics of the incoming call. The information flows are shown in Figure 23 and further explained below: {1} The terminating SIP Pro...
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8.4 State Models
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8.4.1 Mapping SIP message to CAMEL Basic Call State Models
This section deals with how the Originating Basic Call State Model (O-BCSM) Points in Call (PICs) and Detection Points (DPs) or ‘triggers’ are mapped to the appropriate SIP messages. Although a mapping is possible, there is not always the same analogy between the circuit switched environment that the CAMEL BCSM were de...
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8.4.2 Mapping to Originating BCSM for MO calls
The mapping between the SIP methods and responses for O-BCSM relating to Mobile Originating Calls are shown in Figure 24. Only the successful case is described. Further work is necessary to describe all other scenarios. The information flows are further described below : {1} INVITE method arrives at the proxy server, i...
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8.4.3 Terminating BCSM for MT Calls
The mapping between the SIP methods and responses for T-BCSM and Mobile Terminating Call is shown in Figure 25. The information flows further described below : {1} INVITE method arrives at the destination SIP Proxy server. Server/IPSSF determines if a T-CSI exists for the called user {2} T-CSI is analysed and if necess...
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8.4.4 Unsuccessful MT Call Delivery
This subsection explores the mapping and the reporting of the DPs that may be encountered when the call is not successfully established. The information flows are shown in Figure 26 and further explained below: {1} INVITE method arrives at the destination SIP proxy server. Server/IPSSF determines is a T-CSI exists for ...
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8.5 CAMEL Integration
Integration of CAMEL functions with SIP Proxy Server functions may require enhancements to SIP standards or CAMEL standards. Some initial work has been done to identify the standards that may need to be enhanced and to assess the extent of the changes required.
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8.5.1 Impact on SIP Standards
Section 8.4 describes and illustrates how SIP messages may be mapped to O_BCSM and T_BCSM Detection Points (DPs) at the SIP Proxy Server/SSF. When studying the Figures it can be seen that some CAMEL Phase 3 DPs (such as O_Active) have good correspondence with SIP messages at the SIP Proxy Server, while other DPs requir...
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8.5.2 Impact on CAMEL and other UMTS Standards
It is likely that some functional modelling additions and some CAP message information element additions will be needed. It is also likely that some HLR/VLR data and MAP protocol additions may be needed. It is of course very difficult to assess and describe exactly how much effort and meeting time is required to effect...
14ce710049a3c611ebb26f3972649957
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8.6 Service Impacts
The combination of CAMEL and SIP (as described in this report) may support some GSM supplementary services, such as unconditional call forwarding (subject to some re-engineering) and perhaps most operator specific services (depends on the extent of any reduced functionality necessary for integration). Every service nee...
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8.7 Multimedia Evolution
The proposal in this report is focused on voice not multimedia. Control of multimedia services requires further study. However, the proposal does not in any way preclude CAMEL evolution to control multimedia services supported by SIP. It is likely that further enhancements to the protocols and functions listed in secti...
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8.8 Advantages
The following advantages have been identified:  Maximises the re-use of existing functional entities, protocols and services. Such reuse decreases the development and ownership costs allowing existing familiar 2G services to be provided to 3G subscribers at an early stage. Minimum changes to the CSE for the support of...
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8.9 Disadvantages
The following disadvantages have been identified:  This approach is not in line with the work currently underway in ETSI SPAN 3 (Services and Protocols), in particular a work item addressing IN support for voice over IP on the H.323 architecture and associated protocols in association with the TIPHON project.  Introd...
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9 Work in other Standards Groups
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9.1 3GPP
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9.1.1 System Architecture Working Group 2 (S2)
The 3GPP S2 group has overall system architecture responsibility for the GSM/GPRS evolved system within the 3GPP organisation and also has close linkage with the ETSI SMG12 (GSM/GPRS) system architecture group. The S2 group is investigating the architectural impacts and linkages involved with providing IN (CAMEL) based...
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9.2 ETSI
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9.2.1 TIPHON
TIPHON Working Group 7 is studying the implementation of TIPHON networks in a mobile environment, and has been in existence since the beginning of 1999. TIPHON mobility is user and service mobility in the context of the VoIP application. The group has an understanding with 3GPP S2 to liase over IP activities. It is cur...
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9.2.2 SPAN3
ETSI SPAN (Services and Protocol for Advanced Networks) is ETSI’s core competence centre for fixed networks standardisation including IP based networks. SPAN3 (formerly SPS3) is the competence centre for IN Activities, including generic operations for INAP mobility. SPS3 work on Core INAP CS-3 has been split into two...
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9.3 IETF
The Routing area contains the IP Routing for Wireless/Mobile Hosts (mobileIP) Working Group. It has developed routing support to permit IP nodes (hosts and routers) using either IPv4 or IPv6 to seamlessly roam among IP sub-networks and media types. The group has produced an Internet draft entitled “Requirements on Mobi...
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9.4 ITU-T
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9.4.1 SG11
Study Group SG11 is responsible for studies relating to signalling requirements and protocols for telephone, N-ISDN, B-ISGN, UPT, mobile and multimedia communications. SG11 is responsible for most of the Q-Series standards, including Q.931. Questions under study by the group include: 5/11 Intelligent network capability...
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9.4.2 SG16
Study Group16 is responsible for studies relating to multimedia service definition and multimedia systems, including the associated terminals, modems, protocols and signal processing. SG16 is responsible for the H-Series standards, including H.323, as well as parts of the T-, G-, and F-Series. Questions under study by ...
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10 Questions & Answers
Early drafts of this FTR were presented to 3GPP CN WG2a and a small number of questions were raised. The questions and answers are recorded here. Q. In our work, are we considering IN control of RAS signalling or for call control or both? A. Control of RAS signalling is out of scope. Q. How does the architecture suppo...
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11 Conclusions & Recommendations
This report has demonstrated how CAMEL can be used to control VoIP services in an all IP network using H.323 or SIP. The analysis has been carried out at a high level sufficient to identify that further detailed design and specification work should lead to a viable solution provided the architectural assumptions used i...
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1 Scope
The present document describes the statistical theory and concepts applied in the conformance test of the user equipment (UE) so as to improve test speed.
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2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non‑specific. • For a specific reference, subsequent revisions do not apply. • Fo...
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3.1 Definitions
For the purposes of the present document, the following additional terms and definitions apply.
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3.2 Symbols
For the purposes of the present document, the following symbols apply: […] Values included in square bracket must be considered for further studies, because it means that a decision about that value was not taken
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3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply: BER Bit Error Ratio BLER Block Error Ratio DUT Device under Test
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3.4 Equations
Void.
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4 Introduction
This technical report includes two distinct approaches made to determine total test time optimisation. For ease of understanding they are just referred to here as the first and second approach. Furthermore the two approaches differ a little in that they use slightly different terminology.
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4.1 First approach
The first approach is found in clauses 5 and 6. It reflects TS 34.121 in that the symbols, abbreviations and equations are consistent with TS 34.121.
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4.2 Second approach
The second approach is found in clauses 7 to 11 and does not directly reflect TS 34.121 although it does use the existing theory from TS 34.121. The difference is that it refines the theory and derives further approaches for test time reduction. Some of the symbols, abbreviations and equations have local meaning and th...
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5.1 Properties of the Poisson Distribution
Description of a statistical experiment by a distribution function and basic characteristics of the distribution.
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5.2 Equivalence between Poisson Distribution and Chi Square Distribution
Here it is shown, that both distributions are equal. Just the form is different. On the other hand there are two inverse cumulative operations. One of them is useful for our purpose.
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5.3 Confidence interval
In a single test we apply ns samples and measure ne errors. The result can be member of different distributions each characterized by another parameter NE. We ask for two of them: 1) The worst possible distribution NEhigh , containing our measured ne with [D= 0.0085%] probability in the sense 0.000085= (2) ni is the i...
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5.4 Application of the confidence interval to decide the outcome of the test
If we find the entire confidence range, calculated from a single result ne, on the good side of the specified limit we can state: With high probability 1-D, the final NE is better than the limit. If we find the entire confidence interval, calculated from a single result ne, on the bad side of the specified limit we can...
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5.6 Test time reduction
Using 5.4 the outcome of the test is connected with two qualities, a good one and a worse and variable one. Introducing the bad DUT factor M, the quality of the test is now uniform and test time is further reduced.
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5.7 Calculation of the intersection coordinates (maximum number of sample and the normalized test limit)
Calculus for intersection co-ordinates of the early pass and early fail limit.
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5.8 Wrong decision risk F
5.1 to 5.6 applies the wrong decision risk for a single test step D. However it is desirable to have a predefined wrong decision risk for the entire test F. The approach to derive F from D this is explained here.
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5.1 Properties of the Poisson distribution
NOTE: The following text is expressed in terms of BER=bit error ratio. However it can be used for BLER (Block error ratio) as well. Even for 1- Success Ratio, used in RRM delay tests, the theory can be used. With a finite number of samples (ns), the final bit error ratio BER cannot be determined exactly. Applying a fi...
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5.2 Equivalence between Poisson distribution and Chi Square distribution
The experiment, the Poisson distribution is based on, is having observed a certain number of samples (ns), the number of events (ne) is counted to calculate the ratio ne/ns. The experiment, the Chi Square distribution is based on, is having observed a certain number of events (ne), the number of samples (ns) is counted...
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5.5 Test time reduction
Whichever ne we propose as a final stop condition e.g. ne =200, the test can leave the area between the early pass and the early fail limit through the open end of the right side of Figure 5-7. This situation needs an arbitrary pass or fail decision. E.g. pass, if the test hits the vertical 200-error line. This situati...
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5.6 Calculation of the intersection coordinates
initial guess of target number of events root finds the zero of the function target number of events normalized test limit
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5.7 Wrong decision risk F
Provided a single BER trajectory with final BER on the limit hits the early fail limit. If a fail is decided at this instant of the test, the wrong decision risk is as small as D. For each member of a large population of DUTs a wrong decision can happen, with probability D, accumulating to an amount F > D for the entir...
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6 F to D conversion in BER BLER tests
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6.1 Conversion F to D
Annex F.6.1 in TS 34.121 gives a statistical approach for BER BLER tests. It gives early pass and early fail conditions. The formulas for this condition contain the parameter D, the wrong decision probability for a single test step. However it is desirable to have a wrong decision probability for the entire test F. Thi...
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6.2 Introduction
Provided a single BER trajectory with final BER on the limit hits the early fail limit. If a fail is decided at this instant of the test, the wrong decision risk is as small as D. For each member of a large population of DUTs a wrong decision can happen, with probability D, accumulating to an amount F > D for the entir...
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6.3 The simulation procedure
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6.3.1 Equal pass and fail probability
A population of DUTs on the limit is established. Quantity 10 000 Preselected BER 1% An early fail and an early pass limit is established. With D (wrong decision risk) and M (bad DUT factor) With target ne and test limit as a side result. D is tuned in the inner loop M and Fpredefined are varied in the outer loop Duri...
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6.3.2 Unequal pass and fail probability
For statistical test, frequently repeated, a single false fail can fail the composite test. This can be combated by a decreased false fail risk. This costs test time. A single false pass does not have this effect on the composite test. Hence it is not necessary to consume increased test time due to decreased false pass...
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6.4 Result of the simulation: M-F array
Table 6‑1: M-F table 7. Definitions, symbols and abbreviations Definitions, symbols, abbreviations and equations used in the present document are listed in TR 21.905 [5] and TR 25.990 [6].
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7.1 Definitions
For the purposes of the present document, the following additional terms and definitions apply. Wrong Decision Probability: Chance of incorrect judgement based on the given test results. Significance Level: Chance of incorrect judgement based on the given test results. This term is exchangeable with Wrong Decision Prob...
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7.2 Symbols
For the purposes of the present document, the following symbols apply: […] Values included in square bracket must be considered for further studies, because it means that a decision about that value was not taken C Confidence Coefficient (Confidence Level) D Individual Significance Level Dp Individual Significance Leve...
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7.3 Abbreviations
For the purposes of the present document, the following abbreviations apply: BER Bit Error Ratio BLER Block Error Ratio DUT Device under Test pdf Probability Distribution Function CDF Cumulative Distribution Function
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7.4 Equations
Chi-square distribution: of a degree of freedom n where is gamma function. Exponential distribution:
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8 Introduction
BER/BLER measurements are inherently statistical processes, and a statistical approach should be introduced in order to make a BER/BLER test method objective and accurate. In the GSM standard specifications, this has been achieved by introducing "wrong decision probability (significance level)" and "bad DUT factor." Th...
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9 Statistical characteristics of testing processes
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9.1 Exact probability distribution functions
BER/BLER measurements treat phenomena that are characterized as: 1) The experiment consists of a sequence of independent trials. 2) Each trial has two possible outcomes, E (Error) or N (Non Error). 3) The probability of E (r = f(E)) is constant from one trial to another. That is, the BER/BLER measurement can be reduced...
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34.901
9.2 Approximation with continuous distributions
In this section, the notion r for average error ratio is used for average error rate too. The distributions introduced above are exact, but sometimes they are very time-consuming to simulate the process on a computer. So, it is convenient to use appropriate continuous distribution functions that approximate the discret...
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34.901
9.3 Simple test criteria and significance level
For BER/BLER testing, our test can be reduced to a comparison of the measured error rate, R against a threshold. It would follow the procedure like: if R < Rth-p then the DUT passes else if R > Rth-f then the DUT fails else no decision should be made Where Rth-p and Rth-f are the threshold for pass and fail criteria, a...
4131cd5fefdadf4075e3ec0993ed8fe4
34.901
10 Early Pass/Fail termination of testing
4131cd5fefdadf4075e3ec0993ed8fe4
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10.1 Framework of test method
If a UE reported 50 block errors for the first 100 frames, we would intuitively know that the UE should be bad (its average BLER should be higher than 0.01), even though the number of the observed errors is much smaller than 200. We are quite sure about that, since it should be very rare for a UE with an average BLER o...
4131cd5fefdadf4075e3ec0993ed8fe4
34.901
10.2 Early Pass/Fail criteria
As described in the previous section, once the framework of the test procedure is established, a test can be defined by presenting the table of Rth_p, Tdp, and Rth_f. These values will be referred to as "Early Criteria." The requirements for such criteria should be: 1) F should be 0.2 % for BER/BLER measurement, and 5%...
4131cd5fefdadf4075e3ec0993ed8fe4
34.901
10.3 Estimating the test time
The final goal of this report is to reduce the total test time, so each set of criteria should be rated by estimating its test time. This task is fairly simple, and can be done using almost the same simulation program used in the previous section. The sample number at which the measurement is terminated is recorded and...
4131cd5fefdadf4075e3ec0993ed8fe4
34.901
10.4 Minimizing the test time
The criteria set in Section 10.2 ("constant D criteria") were chosen in an arbitrary way, and there is no guarantee that that should give the shortest test time. So, to seek the optimized method, some other criteria that are basically a variation of the "constant D criteria" will be proposed and their test time will be...
4131cd5fefdadf4075e3ec0993ed8fe4
34.901
10.4.1 Truncation
As a matter of fact, while the simple test is terminated at m = 200 (F = 0.2%), the cross point of the criteria is located at m = 374 for the "constant D criteria." Moreover, only few DUTs survive till later stages. So, it seems to be a good idea truncating the procedure at a little earlier stage. This means that Rth_p...
4131cd5fefdadf4075e3ec0993ed8fe4
34.901
10.4.2 Decimation
If the simple tests (comparisons) were done at a smaller number of m, that would result in a smaller F value. In other words, a larger D value can be employed for a certain F value, this can mean a reduced test time since the criteria curve with a higher D value will be located at more left hand side. The real expected...