GSM and UMTS (P17)

Chapter 17: Testing and Type Approval of the Mobile Stations Re´mi Thomas and David Barnes1 17.1 Introduction In this chapter we aim to explain the principles and evolutions of the testi

Chapter 17: Testing and Type Approval of the Mobile Stations Re´mi Thomas and David Barnes1

17.1 Introduction

In this chapter we aim to explain the principles and evolutions of the testing and type approval

of the GSM Mobile Equipment (ME) After having recalled the context at the end of the 1980s (paragraph 17.2), we outline the technical background (paragraph 17.3) and we explain the first step of the type approval, i.e the ‘‘interim type approval’’(paragraph 17.4) Then we describe the TBR regime (paragraph 17.5) and how it evolved to cope with phase 2 (para-graph 17.6) and phase 21 (para(para-graph 17.7) We explain the work of two committees, namely ETSI/SMG7 and TAAB (paragraph 17.8), we give some hints regarding the test tools (para-graph 17.9) Finally in the conclusion (para(para-graph 17.10) we consider the achievements of the GSM type approval and we rapidly explain how the principles of the GSM conformity testing are presently reused by 3GPP for the conformity testing of the UMTS terminals

17.2 The First Steps in 1988–1990

To understand the ideas underlying the first actions for GSM Mobile Stations (GSM MS) testing, it is necessary to recall some elements which were agreed by the GSM community already at the end of the 1980s:

† ME and SIM together form the GSM MS; the Subscriber Identity Module (SIM) is a chip card provided by the network operator to the mobile subscriber, this card contains in particular all the subscription related data;

† Unlike to the SIM card, the ME is not under the control of the network operator, therefore the network operators have to ensure through some testing process that the MEs will be able to provide service and will not cause any damage to the network

There were therefore two overriding criteria Firstly the MSs from different manufacturers should interwork with all networks Secondly the GSM community required that roaming should work from the beginning of the commercial service Today this is seen as a straight-forward feature but this was not the case in those years and this resulted in some strict conformity requirements on the MEs

1 The views expressed in this chapter are those of the authors and do not necessarily reflect the views of their affiliation entities.

Copyright q 2001 John Wiley & Sons Ltd ISBNs: 0-470-84322-5 (Hardback); 0-470-845546 (Electronic)

To cope with these two requirements the GSM community set up two processes:

† A group was established under the leadership of the ‘‘Permanent Nucleus’’ (PN) of the CEPT/GSM committee The mandate of this group, the ‘‘Eleven Series Drafting Group’’ (ESDG), was to specify conformity tests of the ME The tests were produced on a volun-tary basis by experts provided by companies contributing to the GSM standardisation; these tests were included in a GSM specification, namely GSM 11.10;

† A process for the development, purchase and deployment of a test tool implementing the

ME tests defined by the ESDG, this testing tool was called the ‘‘System Simulator’’ as the purpose of this tool was to completely simulate a GSM network

These two tasks were in fact quite ambitious In order to understand the situation, it is useful to consider a general description of GSM 11.10 and the complexities of developing a system simulator

17.3 The Technical Context

17.3.1 Some Insight into GSM 11.10

We give some insights in tests domains which are defined in TS GSM 11.10 the purpose of which is quite ambitious as it aims to cover all the aspects of the ME conformity, both at the air interface and at the SIM/ME interface

17.3.1.1 Radio Tests

This part of the testing checks that the ME is compliant with the radio performance defined in the 05 series of the GSM recommendations Thus a compliant unit will behave in a foresee-able manner This is particularly important in order to enforesee-able a GSM network operator to make a radio design providing all the advantages of the GSM radio performance

The main domains of testing are listed hereafter: transceiver, transmitter, receiver, refer-ence sensitivity, usable receiver input level range, co-channel rejection, adjacent channel rejection, intermodulation rejection, blocking and spurious response, timing advance and absolute delay, access times during handover, temporary reception gaps, channel release after unrecoverable errors

17.3.1.2 Radio Link Management Tests

This comprises the cell selection and reselection tests and the received signal measurements tests

17.3.1.3 Signalling Tests

All the signalling protocols of the radio interface are tested First, this comprises the tests of the layer 2 signalling functions which verify the conformity with the LAPDm protocol defined in GSM 04.06

This comprises as well the layer 3 testing which verifies the conformity with TS GSM 04.08, we indicate rapidly the main domains of testing:

† Handling of unknown, unforeseen, and erroneous protocol data: the purpose of such tests

is to cope with future evolutions of the protocol;

† Test of the elementary procedures for radio resource management: Immediate assignment, normal paging, measurement report, channel assignment procedure, handover, ciphering mode setting, channel release;

† Test of the elementary procedures for mobility management: TMSI reallocation, authen-tication, identification, MM connection;

† Test of the procedures for call control;

† - Finally testing of structured procedures is performed in order to verify that the ME under test is able to perform call set-ups

17.3.1.4 Testing of the SIM/ME Interface

The purpose of these tests is to check the conformity of the SIM/ME interface of the ME as defined in TS GSM 11.11, testing of the SIM itself is not part of TS GSM 11.10

It is tested that the ME is able to retrieve information from the SIM and to update them, for example this comprises the following tests: forbidden PLMNs, location updating and unde-fined cipher key; MS updating forbidden PLMNs, MS updating the PLMN selector list Some physical characteristics of the SIM/ME interface are further verified: mechanical tests, and electrical tests

The test of some services (Short Message Service (SMS), some supplementary services) and of some MS features can be found as well in GSM 11.10

Last but not least, GSM 11.10 comprises tests of speech teleservices and tests of speech transcoding functions

17.3.2 Phased Development of GSM – the 1800 MHz Band

In October 1989 the GSM community chose to develop the GSM standard in phases and to produce a complete set of standards for each phase

Phase 1 of GSM was functionally frozen in January 1990 and it is worth recalling that it only encompassed the 900 MHz band thus excluding the operations in the 1800 MHz band which were called ‘‘DCS 1800’’ In order to specify the DCS 1800, ETSI/SMG created delta-specifications which were to be understood together with the corresponding phase 1 speci-fications For instance there was a specification named ‘‘GSM 11.10-DCS’’ the first version of which was approved by ETSI/SMG in June 1992

The basic phase 2 of GSM was frozen in October 1995; among other decisions it was decided to include DCS 1800 in basic GSM phase 2 This implied that 900/1800 operations (mainly 900/1800 handover and 900/1800 selection/reselection processes) were part of basic phase 2

Then the concept of GSM phase 21 was introduced in order to add continuously new features to the GSM standard It is the choice of each network operator, each network infrastructure manufacturer and each MS manufacturer to implement or not to implement any of the GSM phase 21 features

To achieve this, new sets of functions are added without changing the protocols for the existing ones and without causing incompatibility problems with already existing equipment

In other words, there is an unchanged base which is basic phase 2 as approved in October

1995 and then the phase 21 features are build on it Based of these rules, new releases of the GSM standard were produced: Releases 96, 97, and 98

As a consequence a new version of GSM 11.10 was written for each phase of the GSM standard: a limited number of tests were modified to take into account evolutions of already existing features, and new tests were added in order to test new features

17.3.3 Availability of System Simulators

The key to the testing of GSM MEs for type approval purposes was the availability of a suitable System Simulator (SS) As already explained the operators required a test specifi-cation and an SS that was sufficiently comprehensive to ensure interworking between different manufacturers’ equipment and enable international roaming It was apparent that such a development would be extremly expensive and the burning question was, who should pay?

There was no precedent for regulators to fund such system simulators where the require-ments to ensure interworking were above and beyond those normally required for regulatory purposes A similar situation had existed prior to this in the UK with the introduction of the TACS system and in this case a precedent had been set where the operators concerned had funded the development and purchase of a system simulator

In the UK situation the operators (there were two in the UK at that time, Cellnet and Vodafone) funded the purchase and development of an SS There was then a factor built into the type approval fee for the operators to recover their outlay over a set number of type approvals At that stage of course no-one was sure just how many different terminals would

be produced and eventually type approved Needless to say all estimates were considerably less than the actual number and the financing arrangements worked successfully

A similar approach was therefore considered for GSM and a small number of operators who were members of the GSM MoU undertook to underwrite the development of the SS for GSM type approval This group of operators was known as the ‘‘buyers club’’ and was a vital initiative to get the development and procurement work underway for the delivery of an SS After the delivery of the initial SS it became apparent that it would be unfair for the original buyers club to continue to take the full financial burden of the continued development of the

SS and the necessary test cases The GSM MoU however provided the necessary finance and resources by establishing a separtae company within the MoU called GSM Facilities Limited (GSMFL) It was the purpose of GSMFL to see the development of the SS through to the complete implementation of GSM phase 2

Throughout the lifetime of the buyers club and the GSMFL, Peter Zollman (Vodafone) worked as the project manager for the development of the SS and the associated test cases In this respect his efforts were particularly appreciated in maintaining the project on track and keeping the GSM community informed of the current status

The GSM 1800 (then known as DCS 1800) MEs were not catered for in the GSM SS This was because at that time DCS 1800 was still a separate part of the GSM family However, the DCS 1800 operators faced exactly the same problem as the GSM 900 operators in terms of their requirements for a suitable SS At that time the only networks approaching commercial service were in the UK and One-2-One and Orange jointly funded the initial development and procurement of an SS In actual fact they purchased two simulators

At a later stage it was seen that there was a continuing process of validation of test cases for the SSs and a DCS validation group was set up under the PCN TAEG This group was chaired

by David Nelson (Orange)

17.4 The Interim Type Approval Procedure

17.4.1 The Technical Process

In 1987, the operators who signed the GSM MoU committed themselves to start the GSM service in 1990 Unfortunately the delays in the different developments resulted in delaying the fulfilment of this demanding commitment In fact the phase 1 of the GSM standard was functionally frozen in January 1990 As a straightforward consequence, it was not concei-vable to have GSM network infrastructure on the field in 1990

Nevertheless the situation for the GSM terminals was even more worrying As a matter of fact it appeared in 1990 that it was impossible to foresee when the test of the first GSM ME would be completed Type approval and testing are inevitably blamed as a source of delay in the availability of MSs for a system such as GSM One of the reasons for this is that by the very nature of the standards development process the test specifications can only be produced and finalised once the contents of the core specifications is clearly defined Furthermore, one has to be careful to ensure that the test specifications only reflect what is in the core specifica-tions and that no additional requirements are inadvertently added Finally it is difficult to place a detailed order for test equipment without a comprehensive test specification However, this is effectively what had to happen with the test equipment manufacturer having

to track the changes to the test specifications as they were refined This was further compli-cated by the fact that the test specifications were still trying to track corrections that were made to the core specifications

It was therefore somewhat inevitable that delays were experienced by the extremely ambitious processes described in the previous paragraphs (namely the drafting of GSM 11.10 and the development of the GSM SS):

† significant work was already accomplished for the radio transmission tests but there remained some important work to produce a sufficient amount of signalling tests;

† the delays in the development of the SS were even more worrying, it became obvious that the SS was on the critical path of the GSM commercial opening, in fact it was not possible

to foresee precisely when the SS would be able to test a GSM ME

To cope with this difficult situation two types of actions were undertaken:

† on the standardisation side more efforts were put into the production of the tests, in particular during the first months of 1990 more signalling and protocols experts were involved in ESDG and a ‘‘signalling subgroup’’ was set up;

† regarding the test tools it became obvious that it was necessary to start testing with a tool including less features than the SS

As a result of this the regulators and the GSM operators decided at the end of 1990 to set up the ‘‘Interim Type Approval’’ (ITA) in order to speed up the start of the GSM terminals testing At that time there was considerable discussion between the operators on the minimum level of testing that would be acceptable for ITA One view called for a high level of testing to

ensure confidence in the GSM system However, there was equally a view that said ‘‘we won’t know until we start’’ and there was a need to get terminals into the market place The famous quote from George Schmitt (Mannesmann) at that time was a new meaning for the term GSM – ‘‘God Send Mobiles’’

The discussions came to a head in a meeting in Frankfurt where David Hendon (UK DTI) and Armin Silberhorn (German Ministry) were particularly influential in promoting a compromise that was acceptable to all parties and allowed ITA to go ahead

From a test specification point of view the ITA relied on two principles:

1 reduce the set of tests to be performed;

2 simplify the specification of some tests cases in order that these tests can be performed on a tool simpler than the SS

Item (b) applied particularly to the handover test cases and to the selection/reselection test cases As a matter of fact GSM 11.10 required (and still requires) that a total of eight base stations be simulated in order to perform some handover and selection/reselection test cases This implied having a fine co-ordination of both the radio and protocol activities of eight radio transmitters simulating these base stations It appeared that such a feature was one of the most difficult features to be implemented As a consequence it was decided that in the ITA the simulation of only four base stations was required Evidently this reduces the accuracy of these tests but this was the only solution to speed up the start of the GSM MEs testing The ITA test tool was developed and produced by Rohde and Schwarz according to the requirements of the GSM operators

The ITA specified the type approval of phase 1 GSM MSs Again this meant that this tackled MSs operating in the 900 MHz band only As a consequence it was necessary to set up interim procedures for the type approval of DCS 1800 MSs Technically it was based on GSM 11.10-DCS From a regulatory point of view, it relied on a MoU for DCS 1800 type approval signed by the DTI (UK) and the German Ministry as UK and Germany were the first countries introducing DCS 1800 The MoU was quite significant in that it effectively introduced mutual recognition of type approval between the UK and Germany for DCS 1800 terminal equip-ment This enabled full international roaming between the signatory countries Although signed initially by Germany and the UK, other countries also signed the MoU as GSM

1800 began to spread The MoU was eventually terminated when GSM 1800 equipment became covered by a CTR under the TTE Directive

17.4.2 Additional Procedures

At the time leading up to the introduction of ITA for GSM the type approval was under the basis of what was known as the EC phase 1 Directive This effectively gave the possibility of the mutual recognition of test reports based on what were known as NETs These were European norms for telecommunications and in the case of GSM there was a NET 10 The procedure at that time left a significant number of gaps with regard to the requirements

An early version of the ITA test tool was available mid-1991 The first type approval under the ITA regime was given on 26 May 1992

for GSM terminals At that stage a manufacturer would still have to obtain individual type approval in every country where the ME was to be placed on the market There was no provision for the ‘‘free circulation’’ of the terminals for roamers and there was no procedure to deal with such issues as the allocation of International Mobile Equipment Identities (IMEIs) The GSM MoU was again instrumental in solving a number of these issues and in order to progress work set up a group called the Type Approval Procedure (TAP) group which was chaired by Lilian Jeanty (Netherlands) The group included GSM operators and the type approval authorities involved in the early introduction of GSM

TAP developed the procedures for the allocation of IMEIs so that a unique IMEI could be allocated to each GSM ME Essentially the first two digits of the code were allocated by the TAP to a particular country granting type approval The country concerned could then build

up a unique set of IMEI codes in conjunction with the manufacturers concerned The details for this allocation process were laid down in a Permanent Reference Document (PRD) of the GSM MoU

The TAP group also worked on the issue of free circulation of MSs within Europe In this respect the Nordic countries already had experience with NMT of allowing a customer to take

a terminal from one country to another and use it on the network provided there However, the general concept of unhindered international roaming throughout Europe was something relatively new The TAP group carried out the initial work on a draft CEPT recommendation

to enable international roaming throughout Europe This work was then taken up by the CEPT to produce the necessary ERC decision that formed the basis of free circulation within Europe

The TAP group had no real legal authority in decisions that it made However, there were only a limited number of SSs available for the testing of GSM MEs and this effectively limited the number of countries that were issueing type approval certificates All of the regulatory or notified bodies of those countries were represented in the TAP group and agreed

to abide by the procedures laid down in the PRDs developed by the group

The group reached decisions by consensus and with the agreement of the regulatory bodies involved effectively operated a common European scheme for type approval and free circu-lation of terminals ahead of the TTE Directive

17.5 The European Terminal Directive – Technical Basis for Regulation (TBR) for Phase 1

The ITA provided a pragmatic solution which ensured the availability of the first GSM MSs Nevertheless this emergency solution was not compliant with the EU Directive on terminals (Telecommunication Terminal Equipment Directive 91/263/EEC)

Therefore the GSM community decided in mid-1992 to create Technical Basis for Regula-tion for GSM ME, in accordance with the Terminal Directive

In the following paragraphs we give some insight into the European Directive on terminal equipment and we explain what are the TBRs for GSM MSs, these documents were produced and maintained by the ETSI/SMG which was the ETSI technical committee in charge of the GSM standard

17.5.1 The European Directive on Terminal Equipment

The main purpose of this Directive was to create a community-wide market for terminal equipment This will be accelerated by introducing full mutual recognition based on harmo-nising conditions for the placing on the market of terminal equipment To achieve that, rules deduced from this Directive define a type approval procedure which is common to all member states

According to Article 4 of the European Directive, terminal equipment shall satisfy the following essential requirements:

(a) User safety, in so far as this requirement is not covered by Directive 73/23/EEC; (b) Safety of employees of public telecommunications network operators;

(c) Electromagnetic compatibility requirements in so far as they are specific to terminal equipment;

(d) Protection of the public telecommunications network from harm;

(e) Effective use of the radio frequency spectrum;

(f) Interworking of terminal equipment with public telecommunications network equip-ment for the purpose of establishing, modifying, charging for, holding and clearing real or virtual connection;

(g) Interworking of terminal equipment via the public telecommunications network, in justified cases

(In particular the justified cases comprise the support of services which the Council has decided should be available Community-wide)

Compliance with the essential requirements (a) and (b) shall be presumed for the terminal equipment which conform with the relevant national standards Compliance with the essential requirement (c) is verified under another European Directive Therefore in the following we will only consider essential requirements (d), (e), (f) and (g)

The mutual recognition principle means that type approval granted to a GSM ME in one member state is valid for all member states Once an ME has been type approved it can be placed on the market of all the countries taking part in this agreement This creates the conditions for an open and unified market To be valid, a type approval has to be granted

by a regulatory authority Testing itself is in fact performed by a test house which has been designated by the regulatory authority of its country

The rules which define the type approval for terminal equipment are specified in docu-ments called ‘‘Common Technical Regulations’’ (CTR) For the phase 1 GSM MSs, CTR 5 and CTR 9 applied

In fact the CTRs are short documents which refer to the TBRs The TBRs are technical documents which are produced and maintained by ETSI/SMG, they specify the type approval testing which is to be performed by a designated test house

17.5.2 GSM 11.10 for Phase 1 and TBR for Phase 1

Now we explain the structure of the TBRs and how they rely on GSM 11.10 For each conformance requirement included in a TBR, one or more test purposes are given For each test purpose a single reference is given to the test method in GSM 11.10 As a conse-quence the verification of the conformance requirements outlined in the TBR is based on the

tests described in GSM 11.10 The inclusion of each test is justified by referring to one of the essential requirements (d)–(g)

In GSM phase 1 two TBRs define the regulatory testing of the GSM phase 1 MSs, namely TBR5 which copes with the basic attachment to the network and TBR9 which verifies that the speech teleservice is correctly supported end to end

In TBR5 requirements apply at the air interface and at the SIM-ME interface It is verified that the MS is able to get access to the network and that it does not disturb it, therefore, TBR5 comprises most of the radio tests, radio link management tests, signalling tests and testing of the SIM/ME interface The tests in TBR5 are justified under essential requirements (d), (e) or (f)

In TBR 9 there are requirements to the speech transmission, it is verified that the speech teleservice is correctly provided end to end The tests are justified under essential requirement (g) This is possible because speech teleservice is considered by the European Commission as

a justified case

It shall be noted that other services (e.g fax, some Supplementary Services, SMS) are not justified cases, therefore the testing of the end to end interworking of these services is not part

of the regulatory testing However, an MS providing these services has to perform correctly the basic attachment to the network, in other words it shall be compliant with TBR5

As a summary it can be stated that the European type approval relies on two main sets of documents:

† GSM 11.10 which constitutes the full conformance test suite for GSM;

† the TBRs for GSM which define a subset of GSM 11.10 and the mapping between this subset and the essential requirements

By transition period it shall be understood that type approval was allowed to work until 1 January 1995

17.6 Type Approval and TBRs for Phase 2

In order to take into account the phased approach of GSM, it was decided to issue CTRs and TBRs for the type approval of phase 2 GSM MSs In fact the principles outlined in the previous paragraphs still applied, the only difference being that the CTR regime relied on GSM phase 2,

in other words CTRs and TBRs for phase 2 refer to a subset of TS GSM 11.10 phase 2

TBR 5 and TBR 9, the TBRs for GSM MS phase 1 were approved by ETSI/SMG at their 4bis meeting in Paris in October 1992 The TBR regime was implemented under European Commission Decision 94/11/EC This implemented TBR approval from 1 January 1994 There was a transition period for ITA until 1 January 1995

TBR19 and TBR20, the TBRs for the 900 MHz GSM MEs phase 2 were approved by ETSI/SMG at their 16th meeting in Vienna in October 1995 after the comments of the public enquiry had been treated

TBR19 has a scope similar to that ofTBR5; TBR20 has a scope similar to that ofTBR9, they applied to the GSM 900 phase 2 MSs

At the same time TBRs were created for the GSM MSs operating in the 1800 MHz band (both 1800 MHz only MSs and dual band 900/1800 MSs), they were TBR31 (access, similar

to TBR19) and TBR32 (speech teleservice, similar to TBR20) TBR31 and TBR32 were approved by SMG at their 17th meeting in January 1996 in Edinburgh

17.7 Type Approval and TBRs for Phase 21

The type approval of phase 21 GSM MSs was based on the principles of phase 21 (see paragraph 17.3) These principles yielded the following scheme which was approved by ETSI/SMG of during their 25th meeting in March 1998 in Sophia Antipolis:

1 TBR19 and TBR31 do not evolve because a new phase 21 feature has to be type approved;

2 for a phase 21 feature, a TBR module can be created which relies on TBR19 and TBR31 and which adds some new requirements

The first TBR module which was approved by ETSI/SMG was the one for HSCSD, ETSI/ SMG approved it during their 26th meeting in Helsinki in June 1998

Other examples of TBR modules were TBR module GPRS and TBR module for R-GSM (GSM for railway applications)

17.8 The Role of Two Committees

17.8.1 ETSI/SMG7

From 1988 to 1993, the specification work needed for testing and type approval was performed in different ad-hoc groups At the beginning of 1994, ETSI/SMG decided to create

a sub-technical committee to cope with these matters, this was ETSI/SMG7

It was chaired from January 1994 to mid-1995 by John Alsoe (TeleDenmark), then by Re´mi Thomas (France Te´le´com) from July 1995 to March 1999

ETSI/SMG7 was responsible for GSM 11.10 phase 1, GSM 11.10 phase 2, the phase 1 TBRs, the phase 2 TBRs and the TBR modules

17.8.2 Type Approval Advisory Board

Once it became apparent that an ITA scheme was required it was clear that a body was needed

in addition to the TAP group to oversee the general technical issues, procedures and mechan-isms of ITA A group was therefore established called the ‘‘Type Approval Advisory Board’’ (TAAB) which initially reported to the GSM MoU group The interim type approval scheme introduced for GSM was based on a CEPT recommendation (CEPT REC T/R 21-08) and a resolution by the Technical Regulations Application Committee (TRAC) on the introduction

of NET 10

The TAAB group handled problems encountered during type approval and gave advice to the type approval authorities concerned on actions to be taken to ensure a harmonised and