hash stringlengths 32 32 | doc_id stringlengths 7 13 | section stringlengths 3 121 | content stringlengths 0 2.2M |
|---|---|---|---|
2fc3ee24800832607a894caec2566ade | 101 114 | 5.2.5 Extensibility | ITU-T Recommendations X.680 Amendment 1 [2] and X.681 Amendment 1 [4] define rules of extensibility, enabling the definition of extensions for types and object sets respectively. TR 101 114 V1.1.1 (1997-11) 19 |
2fc3ee24800832607a894caec2566ade | 101 114 | 5.2.5.1 Solution A: Allow use of extension marker in ITU-T Reco | mmendation Z.105 type definitions The extensibility mechanism is intended to allow the intercommunication of implementations of different versions of a specification, one version extending the definition of a type of another version. As shown in the following example, ITU-T Recommendation Z.105 [9] could benefit from the introduction of extensibility. Consider the type Mytype defined in a protocol specification as follows: /* MyType can be extended */ newtype MyType SEQUENCE { a INTEGER, ... } ; A new version of the protocol specification could define MyType as follows: newtype MyType SEQUENCE { a INTEGER, ..., b BOOLEAN } ; An implementation of the old version and an implementation of the new version would be able to exchange message parameters of type MyType. Nevertheless access to field b by the new version for messages coming from the old version could result in execution errors. The specification should be written in such a way this cannot occur, for example, by testing first the presence of field b in the received message. Support of extensibility by ITU-T Recommendation Z.105 [9], will affect the grammar (addition of the ellipsis notation), and the modelling of ASN.1 ENUMERATED, SEQUENCE, SET and CHOICE, into SDL equivalent constructs. A Present operator could be added for every field following the extension mark (...). In the above example operator Bpresent can be used to test the presence of field b. From the syntactic point of view the impact on ITU-T Recommendation Z.105 [9] will be: <module definition> ::= <module> definitions [<tagdefault>] [<extensiondefault>] ::= begin [<modulebody>] end <extensiondefault> ::= extensibility implied NOTE: In accordance to the current ITU-T Recommendation Z.105 [9], the possibility to express exceptions has been omitted. <enumerated> ::= enumerated { {<name number>}+ [, ...] { , <name number> }* } <sequence> ::= { sequence | set } { { [ { <elementsort> }+ [ , ... ] { , <elementsort> }* ] | ... } } <choice> ::= choice { [ { <namedsort> }+ [ , ... ] { , <namedsort> }* ] } <range condition> := { <range> }+ [ { , | | } ... ] { { , | | } <range> }* |
2fc3ee24800832607a894caec2566ade | 101 114 | 5.2.6 Encoding | TTCN allows the specification of the encoding rules for PDUs (either ASN.1 or tabular ones). The reference to the encoding standard (BER, PER etc.) is in free text. Contrary to TTCN, SDL does not support the definition of the encoding to be used. This problem is not specific to ITU-T Recommendation Z.105 [9] but is more an ITU-T Recommendation Z.100 [7] general problem. Nevertheless it is emphasized when using ASN.1 data for which encoding is usually associated. The possibility to express encoding in ITU-T Recommendation Z.105 [9] could be a valuable extension. The advantages are: • in some cases the encoding is part of the protocol specification. SDL, enhanced with encoding, will thus cover more extensively protocol specifications; TR 101 114 V1.1.1 (1997-11) 20 • code generators based on SDL could be extended to treat the encoding as shown in figure 2. This report identifies the need to specify: • the default encoding for a whole package/system/block; • specific encoding for a type. In a way similar to TTCN the encoding could be split into: • encoding rules = reference to a standard; • encoding variations = reference to a section of the standard. ITU-T Recommendation Z.105 [9] explicitly states that tags are ignored. If the encoding is to be incorporated to ITU-T Recommendation Z.105 [9] this would be no more true because encoding needs the tag information. Either the mapping takes into account the tags, or the mapping is considered as incomplete and a code generator cannot rely uniquely on the SDL equivalent form of an ASN.1 type but has to consider the source ASN.1 form. TR 101 114 V1.1.1 (1997-11) 21 TTCN Abstract Test Suite Data types in ASN.1 Behaviour in SDL Specification of encoding possibly referring to the X.690 serie Specification of encoding possibly referring to the X.690 serie Code generation with tool A Test specification Protocol specification Import Import Communication using the Transfer Syntax Protocol implementation 1 Internal representation of data (tool A dependent) Decoder Encoder Protocol implementation 2 Internal representation of data (tool B dependent) Decoder Encoder Code generation with tool B Executable Test Suite Internal representation of data (tool C dependent) Decoder Encoder Derivation with tool C Adaptat ion Figure 2: Use of encoding information by code generators 6 The Problems and issues associated with the use of ASN.1 94 and TTCN This clause considers the problems associated with the integration of ASN.1 94 with TTCN as defined in ISO/IEC 9646-3 [11]. The clause is split into two main parts, "Problems with TTCN Edition 2" and "TTCN Extensions Necessary to Support New ASN.1 94 Features". TR 101 114 V1.1.1 (1997-11) 22 "Problems with TTCN Edition 2" considers problems associated with the current TTCN specification and the limited ASN.1 94 it supports. As it stands, the standard is ambiguous as to exactly what is supported and how it interworks with ASN.1. The "Problems with TTCN Edition 2" clause is structured as a list of problems together with associated proposed solutions. In general the solutions proposed fall into one of two categories shown graphically in figure 3. Solve problems by extending TTCN to support all ASN.1 94 features Solve problems by cutting down X.680 productions to fit TTCN capabilities. Current TTCN Standard Proposed solutions TTCN ASN.1 < X.680 No X.681 - X.683 Full ASN.1 94 X.681 - X.683 supported Figure 3: Possible solution paths to rectify TTCN problems The first of these categories involves cutting out any features of ASN.1 94 that do not fit the current TTCN standard. Implementing such solutions leads to a TTCN standard that only supports a subset of ITU-T Recommendation X.680 [1] and provides no support for ITU-T Recommendation X.681 [3], X.682 [5] and X.683 [6]. The second category of solutions proposes extensions to the TTCN standard to support the new ASN.1 94 features. If these solutions are implemented the TTCN standard could be fully ASN.1 94 compliant. Solutions in the first category are, in general, less radical and easier to implement. However this solution path should only be seen as a temporary measure because eventually TTCN must support the defined ASN.1 standard which is ASN.1 94. The second part of the clause goes on to consider extensions to the TTCN specification to encompass the ASN.1 94 functionality at present not supported. For each new feature there is a clause containing a description together with some possible solutions and consequences of these solutions. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1 Problems with TTCN Edition 2 | This clause categorizes and describes the problems associated with the current TTCN specification and the use of ASN.1 94. Many of the proposed solutions require the TTCN specification to support new features from ASN.1 94. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1 Realization of TTCN BNF | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.1 Description | The current TTCN BNF is not consistent with respect to the ASN.1 94 definitions because they include many features which have no support within the TTCN environment. The TTCN BNF references Value and Type definitions from ITU-T Recommendation X.680 [1]. Within the definitions of these terms X.680 [1] uses productions from X.681[3] (Information Object Specification) and X.683 [6] (Parametrization of ASN.1 Specifications). The current TTCN environment provides no support for the former and only partial support for the latter (extending TTCN to support these features is considered in subclause 6.2). To illustrate the problem, in rule 122 in ISO/IEC 9646-3 [11] specification states : 122 ASN1_Type ::= Type /* REFERENCE - Where Type is the non-terminal defined in ISO/IEC 8824-1: 1994 ...*/ TR 101 114 V1.1.1 (1997-11) 23 In the ISO/IEC 8824-1: 1994 (ITU-T Recommendation X.680 [2]) specification it is stated: Type ::= BuiltinType | ReferencedType | ConstrainedType BuiltinType ::= BitStringType | BooleanType | CharacterStringType | ChoiceType | EmbeddedPDVType | EnumeratedType | ExternalType | InstanceOfType | IntegerType | NullType | ObjectClassFieldType | ObjectIdentifierType | OctetStringType | RealType | SequenceType | SequenceOfType | SetType | SetOfType | TaggedType ReferencedType ::= DefinedType | UsefulType | SelectionType | TypeFromObject | ValueSetFromObjects DefinedType ::= Externaltypereference | typereference | ParameterizedType | ParameterizedValueSetType The underlined identifiers have no meaning within the TTCN environment because information objects and type parametrization are not supported in the current version of TTCN. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.2 Solution A: Redefine ASN.1 productions | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.2.1 Solution description | Redefine a set of ASN.1 productions removing all references to the new features introduced by ASN.1 94. The required production redefinition's are shown in appendix A. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.2.2 Solution consequences | The consequences of this solution are: • this solution has the disadvantage of increasing the divergence between the standardized ASN.1 language and the ASN.1 dialect supported by TTCN. It requires non-trivial redefinition of ASN.1 productions within TTCN; • any existing ASN.1 94 module that makes use of any of the new features must be rewritten before it can be used within TTCN; • this solution could be used as a short term pragmatic solution to provide a consistent TTCN specification. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.3 Solution B: Extend TTCN to support ASN.1 94 features | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.3.1 Solution description | Extend TTCN to support the new features introduced in ASN.1 94. This extension of the TTCN specification to support parametrization and information objects is considered in detail in the second part of this clause. TR 101 114 V1.1.1 (1997-11) 24 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.1.3.2 Solution consequences | In the medium term this solution has the clear advantage that we are actually using the defined ASN.1 specification within TTCN not a redefined dialect. The consequences however are far ranging and will require careful consideration. The consequences are explained in detail in subclauses 6.2.4 and 6.2.5. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2 Semantic problem with DefinedValue Extension | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1 Description | This clause describes the problems associated with the redefinition in TTCN rule 739 of the ASN.1 identifier DefinedValue from: DefinedValue ::= Externalvaluereference | valuereference | ParameterizedValue To: DefinedValue ::= ConstraintValue&Attributes | valuereference | ParameterizedValue DefinedValue is included in the following ASN.1 definitions. In each case it is possible to produce syntactically valid constructs which have no sense or undefined behaviour. In some cases the static semantics defined in ITU-T Recommendation X.680 [1] limit the type that can be produced from DefinedValue but since this specification is referring to a different specification of DefinedValue the meaning in the TTCN context is not definitive. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1.1 NumberForm | If we consider the production NumberForm within the ASN.1 standard: NumberForm ::= number | DefinedValue From the redefinition of DefinedValue, NumberForm can be validly defined as an TTCN constraint e.g., NumberForm ::= "?" The NumberForm production is used in the definition of ObjectIdentifierValue in the following way: ObjectIdentifierValue ::= "{" ObjIdComponentList "}" | "{" DefinedValue ObjIdComponentList "}" ObjIdComponentList ::= ObjIdComponent | ObjIDComponent ObjIdComponentList ObjIdComponent ::= NameForm | NumberForm | NameAndNumberForm Using these productions it is possible to produce the following: ObjectIdentifierValue ::= "{" "6" "5" "4" "?" "}" If we further consider the following productions for SymbolsFromModule which use ObjectIdentifierValue: SymbolsFromModule ::= SymbolList FROM GlobalModuleReference GlobalModuleReference ::= modulereference AssignedIdentifier AssignedIdentifier ::= ObjectIdentifierValue | DefinedValue | empty Using these productions it is possible to produce the following syntactically valid construct SymbolsFromModule ::= SymbolList FROM "{" "6" "5" "4" "?" "}" TR 101 114 V1.1.1 (1997-11) 25 In this case the ObjectIdentifierValue must consist of a sequence of positive numeric values which uniquely and unambiguously identify an object in the object identifier tree. The concept of adding constraints to such a value, as shown above, has no sense. Which ASN.1 module should these symbols be imported from ? |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1.2 CharsDefn | DefinedValue is also used in the definition of CharsDefn: CharsDefn ::= cstring | DefinedValue From the definition of CharacterStringList: CharacterStringList ::= "{" CharSyms "}" CharSyms ::= CharsDefn | CharSyms "," CharsDefn The following production is theoretically possible: CharacterStringList ::= "{" "abc", "?" , "def" "}" Such a constraint within a list of characters appears inappropriate. It could be argued that clause 34.8 in ITU-T Recommendation X.680 [1] already provides static semantics to cover this case. It states " The DefinedValue in CharsDefn shall be a reference to a value of that type." Since this clause is referring to a different definition of DefinedValue, i.e. the true ASN.1 definition, its applicability is ambiguous here. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1.3 ExceptionIdentification | The definition of ExceptionIdentification within the ASN.1 standard also uses DefinedValue: ExceptionIdentification ::= SignedNumber | DefinedValue | Type ":" Value Using the productions: Constraint ::= "(" ConstraintSpec ExceptionSpec ")" ExceptionSpec ::= "!" ExceptionIdentification | empty The following valid construct can be produced: Constraint ::= "(" ConstraintSpec "!" "?" ")" Within ASN.1 the ExceptionSpec is used to define either a value or a type and value associated with a constraint violation (the constraint is defined before the ExceptionSpec). The ability to define constraints within the ExceptionSpec itself makes no sense. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1.4 NamedNumber | In the ASN.1 definition of NamedNumber the DefinedValue production is also used: NamedNumber ::= identifier "(" SignedNumber ")" | identifier "(" DefinedValue ")" Considering the definition of IntegerType: IntegerType ::= INTEGER | INTEGER "{" NamedNumberList "}" NamedNumberList ::= NamedNumber | NamedNumberList "," NamedNumber TR 101 114 V1.1.1 (1997-11) 26 We can define constructs such as: IntegerType ::= INTEGER "{" one "(" "1" ")" "," any "(" "?" ")" "}" In this example names ought to be provided for specific values within the defined type. The ability to use a constraint in this list makes no sense. The definition NamedNumber is also used in the EnumeratedType production: EnumeratedType ::= ENUMERATED "{" Enumeration "}" Enumeration ::= EnumerationItem | EnumerationItem "," Enumeration EnumerationItem ::= identifier | NamedNumber Using these productions it is therefore possible to construct syntactically valid constructs such as: EnumeratedType ::= ENUMERATED "{" one "(" "1" ")" "," any "(" "?".")" "}" In this example the list of possible enumerated values for an enumerated type ought to be defined, again the constraint has no place here. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1.5 NamedBit | The definition of NamedBit also references the DefinedValue production: NamedBit ::= identifier "(" number ")" | identifier "(" DefinedValue ")" The NamedBit production is used in turn in the definition of BitStringType: BitStringType ::= BIT STRING | BIT STRING "{" NamedBitList "}" NamedBitList ::= NamedBit | NamedBitList "," NamedBit Using these production the following syntactically valid ASN.1 construct is possible: BitStringType ::= BIT STRING "{" powerOn "(" "1" ")" "," any "(" "?" ")" "}" The specification of a constraint within this type definition makes no sense. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.1.6 ClassNumber | The ASN.1 definition of ClassNumber uses the production for DefinedValue: ClassNumber ::= number | DefinedValue The ClassNumber production is in turn used in the definition of Tag: Tag ::= "[" Class ClassNumber "]" Class ::= UNIVERSAL | APPLICATION | PRIVATE | empty Using these production we can obtain: Tag ::= "[" UNIVERSAL "?" "]" TR 101 114 V1.1.1 (1997-11) 27 This again clearly makes no sense. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.2 Solution A: Static semantic checks | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.2.1 Solution description | Develop a rigorous set of static semantic statements which explicitly exclude the possibility of any of the above described problems. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.2.2 Solution consequences | The consequences of this solution are: • this solution will require effort in the definition of the required static semantics. In effect this solution is trying to patch-up an existing suspect solution (the redefinition of DefinedValue) as such it is depreciated as a long term solution; • this solution might be acceptable as a short term pragmatic approach. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.3 Solution B: Separation of value and constraints within | TTCN BNF |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.3.1 Solution description | Rework TTCN productions to remove the problems described above. This could be done by separating out the Value and constraints productions. The semantic problems with the TTCN DefinedValue extension are caused by allowing the use of constraints at inappropriate places within the ASN.1 productions. In the current standard there is the single ConstraintValue&Attributes entry point from ASN.1 into TTCN. This entry point provides access to all TTCN values (test case variables, PIXIT values etc.) and constraints (any, any or omit, etc.). If we could separate these two production paths (values and constraints) it might be possible to selectively pass only the appropriate productions into the ASN.1, i.e. redefine the ASN.1 definition to include at various places TTCN values, TTCN constraints or both as semantically valid. It should be noted that any development of the TTCN language, due to the inherent grammar type, is a difficult task. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.3.2 Solution consequences | This solution would require a major reworking of the TTCN specification. The magnitude of the effort required and the quality of the final solution are as yet unclear. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.4 Solution C: Re-implement functionality using ASN.1 feat | ures |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.4.1 Solution description | Re-implement the existing functionality using ASN.1 parametrization and ASN.1 constraint extensions. This solution would use ASN.1 parametrization (see subclause 6.2.4) to pass values (such as test suite variables or constants) from TTCN to ASN.1. The TTCN constraint types, such as "omit" or "any" would need to be standardized into the ASN.1 language. This solution solves the stated problems because it separates the value and constraints paths. TTCN can only pass values to ASN.1 (possibly types also). If the types are consistent for the TTCN and ASN.1 environments these values should always be semantically valid. By defining the constraints with in the ASN.1 the existing BNF restricts the use of these constraints to valid locations. TR 101 114 V1.1.1 (1997-11) 28 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.2.4.2 Solution consequences | The consequences of this solution are: • the redefinition of DefinedValue would no longer be necessary; • in principle this solution requires very little extra effort for TTCN apart from support for ASN.1 94 value parametrization; • the main problem is the need to add TTCN constraint types into the ASN.1 standard; • this is the preferred long term solution as it provides a clean modular syntax between TTCN and ASN.1 while retaining the desirable functionality of the current system without the associated errors. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.3 Syntactic problem with DefinedValue extension | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.3.1 Description | The TTCN redefinition of DefinedValue has the consequence that in certain circumstances the syntax of an ASN.1 clause can be ambiguous. An example of this behaviour can be demonstrated using the BuiltinValue production: BuiltinValue ::= ... | SequenceValue | SequenceofValue | ... | Where: SequenceValue ::= { NamedValue, NamedValue, ...} SequenceofValue ::= { Value, Value, ...} NamedValue ::= identifier Value With the TTCN extension to DefinedValue it is possible to reach an expression through an ASN.1 value, i.e. Value :: BuiltinValue | ReferencedValue ReferencedValue ::= DefinedValue | ValueFromObject DefinedValue ::= ConstraintValue&Attributes | typereference | ParameterizedType | ParameterizedValueSetType ConstraintValue&Attributes ::= ConstraintValue ValueAttributes ConstraintValue ::= ConstraintExpression | MatchingSymbol | ConsRef ConstraintExpression ::= Expression This relationship leads to the following conflicting situation: BuiltinValue ::= { identifier1 - 73, ...} There are two ways of interpreting this example. If "-" is a unary operator then - 73 is a value, therefore the identifier1 - 73 must be a NamedValue. In this case the example resolves to a SequenceValue. On the other hand if we consider "-" as a binary operator then the term identifier1 - 73 is an expression, hence it is equivalent to a Value. In this case the example resolves to a SequenceofValue. TR 101 114 V1.1.1 (1997-11) 29 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.3.2 Solution A: Define TTCN lexical rule | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.3.2.1 Solution description | Considering this problem in isolation one solution would be to formalize "normal" mathematical practice into the syntax, i.e. - 73 /* The space between the operator and value indicates this is an expression */ -73 /* There is no space between the operator and value, therefore this a negative value */ This rule could perhaps be usefully introduced into the entire syntax. This opportunity could be used to clearly define lexical rules for TTCN NOTE: If this solution is implemented the problem of visually distinguishing between - 73 and -73 within the graphical form becomes important. Perhaps some visual clue to differentiate these two cases would be useful. This visual clue could be specified in the TTCN standard at the discretion of the tool developers. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.3.2.2 Solution consequences | The consequences of this solution are: • this change appears straight forward; • the only foreseen negative consequences is backwards compatibility with existing test-suites. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.4 ASN.1 94 entry point | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.4.1 Description | Within the TTCN specification rule 739 references a ASN.1 94 production from ITU-T Recommendation X.680 [1] for DefinedValue. The production is referenced as: DefinedValue ::= Externalvaluereference | valuereference However the actual definition is: DefinedValue ::= Externalvaluereference | valuereference | ParameterizedValue |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.4.2 Solution A: Correct ASN.1 94 production reference | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.4.2.1 Solution description | Incorporate the correct definition from ITU-T Recommendation X.680 [1] into the TTCN specification. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.4.2.2 Solution consequences | The consequences of this solution are: • the consequence of using this definition is that parametrized values are explicitly defined in the ASN.1 productions instead of being coerced into ASN.1 by the redefinition of DefinedValue; • this could be used as the first step in solving the problems associated with the DefinedValue redefinition described in clause 6.1.2. TR 101 114 V1.1.1 (1997-11) 30 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5 ASN.1 reserved words | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.1 Description | The ASN.1 reserved words defined in the TTCN specification table A.3 specify the reserved words from ASN.1 90 not ASN.1 94. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.2 Solution A: Include subset of ASN.1 94 keywords | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.2.1 Solution description | Change the TTCN specification to include a subset of the ASN.1 94 keywords. The chosen subset includes all keywords associated with the core ITU-T Recommendation X.680 [1] specification but omits the keywords associated with information objects. The explicit changes to the table are: Remove: ANY DEFINED Add: ALL BMPString CHARACTER CONSTRAINED EXCEPT INTERSECTION ISO646String ObjectDescriptor UNION UNIQUE UniversalString |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.2.2 Solution consequences | The consequences of this solution are: • the new types introduced as keywords should be supported within TTCN (see clause 6.2.1); • this solution is still not fully compatible with ASN.1 94 because it does not include all the keywords. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.3 Solution B: Include all ASN.1 94 keywords | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.3.1 Solution description | Add the complete ASN.1 94 keywords list to the TTCN specification. In addition to the changes specified in solution A the following additional keywords should be added. It should be noted that these additional keywords relate to features at present not supported by TTCN. ABSTRACT-SYNTAX AUTOMATIC CLASS EMBEDDED TYPE-IDENTIFIER INSTANCE PDV SYNTAX TR 101 114 V1.1.1 (1997-11) 31 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.1.5.3.2 Solution consequences | The consequences of this solution are: • the list of reserved keywords will be fully compatible with the ASN.1 94 specifications; • if it is decided not to support all the ASN.1 94 features within TTCN, this solution may define keywords which have no associated meaning within TTCN. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2 TTCN extensions to support new ASN.1 94 features | This clause considers extensions to the TTCN standard to support new features introduced in ASN.1 94. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1 New ASN.1 94 types | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.1 Description | For ASN.1 and TTCN to function together there must be a clear definition of the type mapping between the two environments. With ASN.1 90 this lead to TTCN using the same type definitions for the base types. ASN.1 94 introduces a number of new types into the language description. Some of these types are straightforward to introduce into TTCN but others are associated with the new features which currently are not supported by TTCN. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.2 Solution A: Support subset of ASN.1 94 types | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.2.1 Solution description | Extend the TTCN specification to support a subset of the new types introduced by ASN.1 94 . The subset includes all the types which are straight-forward to add to TTCN. These types are : BMPString UniversalString |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.2.2 Solution consequences | The consequences of this solution are: • TTCN would not be fully type compatible with ASN.1 94. The incompatible types would be those associated with information objects; • although requiring considerable effort (especially in the case of universal string) this solution avoids any difficult implementation problems. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.3 Solution B: Support all ASN.1 94 types | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.3.1 Solution description | Extend the TTCN specification to support all of the new types introduced by ASN.1 94. The list of new types would be: BMPString UniversalString EMBEDDED PDV INSTANCE OF TR 101 114 V1.1.1 (1997-11) 32 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.1.3.2 Solution consequences | The consequences of this solution are: • the TTCN specification would be fully compatible with the ASN.1 94 specification in terms of defined types; • the last two types are defined in the ASN.1 94 specification in terms of information objects. If it is decided not to support information objects within TTCN then these types could not be fully implemented. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2 AUTOMATIC tagging | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.1 Description | ASN.1 94 introduces the feature of AUTOMATIC tagging. This provides a new tagging mode in addition to the existing IMPLICIT and EXPLICIT. When AUTOMATIC tagging is selected the system will automatically insert any necessary tags within the associated module without the need for user intervention (N.B. the user still has the choice to override the AUTOMATIC mechanism for specific constructs by explicitly defining tags). The ITU-T Recommendation X.680 [1] clause "Guidelines for the use of the ASN.1 notation" recommends always to use AUTOMATIC tagging in the development of new modules. This feature is therefore likely to be used in many, if not all, new ASN.1 modules. AUTOMATIC tags is selected from the ASN.1 module header. Since TTCN only allows ASN.1 type definitions not module definitions there is no current mechanism for selecting the tagging regime within TTCN (it is by default EXPLICIT). Since the potential effort to convert the type definitions in an ASN.1 module using AUTOMATIC tagging into type definitions using explicit tagging is large and error prone, a mechanism to introduce tagging regimes into TTCN should be found. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.2 Solution A: No support for AUTOMATIC tagging | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.2.1 Solution description | Provide no support for AUTOMATIC tagging. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.2.2 Solution consequences | The consequences of this solution are: • the TTCN ASN.1 type declarations are not fully compatible with type declarations within ASN.1 94 modules; • ASN.1 type declarations taken from modules using AUTOMATIC tagging will have to be carefully rewritten for the TTCN environment precisely re-implementing the translations to the syntax that the AUTOMATIC tagging produces. For a complex hierarchical type this is a non-trivial task. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.3 Solution B: Support for AUTOMATIC tagging | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.3.1 Solution description | Introduce an option into the TTCN ASN.1 type proforma to enable the user to specify the tagging regime to be used in the table. In terms of the BNF this would be analogous to the ASN1_Encoding option added to the value production, i.e.: ASN1_Type ::= Type [ASN1_Tagging] ASN1_Tagging ::= EXPLICIT TAGS | IMPLICIT TAGS | AUTOMATIC TAGS | empty If no tag type is defined, EXPLICIT tagging is assumed. TR 101 114 V1.1.1 (1997-11) 33 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.2.3.2 Solution consequences | • in terms of tagging this solution will bring TTCN into line with the ASN.1 94 specification. Type declarations can be directly transposed or referenced from ASN.1 94 modules; • all ASN.1 "type" proformas will need to be extended (new entry in header) to allow specification of the tagging type. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3 Extensibility | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.1 Description | In principle extensibility provides a mechanism for future compatibility by defining a syntax which will accept elements not defined in that syntax. ASN.1 94 allows extensibility to be specified within a syntax definition. The extensibility can either be specified explicitly using the extension marker "..." or globally across an ASN.1 module by addition of an optional field in the module header. The extension marker can be placed in the definition of ENUMERATED TYPE, SEQUENCE, SET and CHOICE. The effect of the extension marker is to disable error generation when the received element does not match the specified syntax of the associated type. At first sight the idea of extensibility seems to be mutually exclusive in regards to conformance testing. However since it is often the case that the test purpose only requires the checking of certain specific parameters, this mechanism could actually be used as a useful addition to provide future compatibility to test suites especially for postambles and preambles. This feature has the potential to increase flexibility and life span of TTCN test suites. It is recommended that the optional header field to specify automatic extensibility is not incorporated into TTCN. In a conformance testing environment explicit specification within the type is preferable to implicit definition, i.e. something explicitly written in the type specification is easier to see and understand than an optional header field. The extensibility feature also requires consideration of the associated transfer syntax. For some encoding rules, most notably PER as defined in ITU-T Recommendation X.691 [14], the extension marker is visible in the transmitted bytes. In such a case if the language used to define the data types for conformance testing cannot support extension markers the transfer syntax of the associated Implementation Under Test (IUT) might be impossible to reproduce within the testing system. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.2 Solution A: No support for extensibility | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.2.1 Solution description | Provide no support for extensibility. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.2.2 Solution consequences | The consequences of this solution are: • the future compatibility of TTCN specified test suites and hence test suite life, might be reduced; • the ASN.1 defined within TTCN will not be fully compatible with the ASN.1 94 specifications; • this solution removes any risk associated with using extensibility during conformance testing. • Test suites for an IUT using encoding rules where the extensibility marker is visibly encoded (e.g., PER) would be extremely difficult or impossible to write using standard TTCN. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.3 Solution B: Support for extensibility | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.3.1 Solution description | Support the extension marker and explicit extensibility within the ASN.1 syntax for TTCN. TR 101 114 V1.1.1 (1997-11) 34 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.3.3.2 Solution consequences | This solution provides the potential benefits in terms of test suite life and direct use of existing ASN.1 94 module specifications. It also removes limitations on the testable transfer syntax. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4 Parametrization | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.1 Description | The current TTCN specification supports only a part of the possible ASN.1 94 parametrization features. This subclause describes the current TTCN support and then considers possible extensions to allow the use of the remaining ASN.1 94 parametrization features. At present TTCN provides value parametrization for constraint declarations. This means values from constants, test suite variables or PIXITs can be passed into a constraint. ASN.1 94 supports the idea of value parametrization for the value notation in a similar way to TTCN. In addition however ASN.1 94 allows value parameters to be used in type notation for definition of constraints. ASN.1 94 also includes the concept of generic type parametrization. For example, consider the following definition: MESSAGE { PDU_Type } ::= SEQUENCE { ASP ASP_Type, PDU PDU_Type } This defines the parametrized type MESSAGE{}. Within the body of the protocol this parametrized type can be used to define further types. For example: SetupMessage ::= MESSAGE { Setup_PDU } Which has the meaning: SetupMessage ::= SEQUENCE { ASP ASP_Type, PDU Setup_PDU } At present TTCN supports a limited form of type parametrization in the form of PDU parameter in ASP type definitions. The addition of generic type parametrization into TTCN would provide a powerful new feature. For example, it could provide the ability to define elements of a protocol from the Protocol Implementation eXtra Information for Testing (PIXIT) list. This would allow far greater flexibility to be introduced into ATS's allowing straight forward customization for a specific System Under Test (SUT). On the other hand type parametrization has a large impact on TTCN compilation. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.2 Solution A: Value parametrization from TTCN | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.2.1 Solution description | Support value parametrization of constraints only, using the existing TTCN syntax. In this solution the TTCN BNF provides the definition for parameter list and referencing the parameter list. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.2.2 Solution consequences | The consequences of this solution are: • this solution does not support type parametrization; • this solution is not syntactically compatible with the ASN.1 94 parametrization specification, i.e., TR 101 114 V1.1.1 (1997-11) 35 Using TTCN BNF the parameter list takes the form: ( name1:TYPE1; name2:TYPE2) Using the ASN.1 94 specification the same parameter list takes the form: { TYPE1:name1, TYPE2:name2} This solution therefore requires any parametrization contained within an existing ASN.1 94 modules to be rewritten entirely before these definitions can be used within TTCN; • this solution is depreciated because it leaves two incompatible mechanisms for providing parametrization. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.3 Solution B: Value parametrization from ASN.1 94 | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.3.1 Solution description | Support value parametrization of constraints by altering the TTCN specification to make use of the ASN.1 value parametrization. In this solution the ASN.1 94 specification would define the syntax of parameter lists and in the case of ASN.1 types the referencing of that parameter list. More effort is required to better define the changes necessary for this solution. In effect this solution moves the value parametrization from TTCN to ASN.1 for ASN.1 types. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.3.2 Solution consequences | The consequences of this solution are: • this solution is ASN.1 94 compliant. It provides a single unified mechanism for passing parameters into ASN.1 value notation; • the syntax of parameter passing into ASN.1 constraints and non-ASN.1 constraints would potentially be different. This problem would hopefully be rectified during the investigation of the necessary TTCN BNF changes; • this solution has the potential to provide a unified value parameter syntax for TTCN and ASN.1; • this solution provides no type parametrization. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.4 Solution C: Value and type parametrization from ASN.1 9 | 4 |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.4.1 Solution description | Full support for ASN.1 94 parametrization. This involves providing value and type parametrization. The main steps in addition to those described in solution B are: • change parameter list definitions to ASN.1 94 syntax; • addition of type parameters to ASN.1 constraint definitions; • addition of type parameters to ASN.1 types definitions; • support the definition of types within the PIXIT. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.4.4.2 Solution consequences | The consequences of this solution are: • the possibility to directly use any parametrized type definitions from pre-defined ASN.1 modules; • the main consequence of this solution is the TTCN system can no longer resolve all types at compile time of the Abstract Test Suite (ATS). That is to say that if a type parameter is defined from the PIXIT list the definition of this type might not be available at ATS compile time. This introduces the idea of a meta or open type; TR 101 114 V1.1.1 (1997-11) 36 • the meta (or open) type is used to represent a type which is unresolved. In many ways this concept is analogous to the ANY type available in ASN.1 90 (but removed in ASN.1 94). |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5 Information objects | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.1 Description | Information objects are the macro replacement mechanism defined in ASN.1 94. In principle information objects are a form of generic table which allow the association of specific sets of field values or types. The greatest single advantage of Information objects is they are machine processable. TTCN has never supported macro definitions within ASN.1. However the semantics of the macro notation were not directly machine processable. Looking at the existing use of information object within standards it appears there use is more wide-spread than macros were. Often information objects are used as a fundamental structuring mechanism. In ASN.1 94 some of the defined types within the language are defined in terms of information objects (these types are TYPE-IDENTIFIER, ABSTRACT-SYNTAX and INSTANCE-OF). Any system than cannot support information objects may have difficulties to provide these built-in types. If TTCN does not support information objects then any existing ASN.1 modules using this feature must be transformed before it can be used within TTCN. Such a transformation and involves converting an information object set into a type containing a CHOICE with all the possible field types. The validity of this transformation is dependant on the transfer syntax. If the required encoding rules make the CHOICE visible in the transfer syntax (e.g., PER) this transformation is invalid (changes the bits transmitted on the line). It follows that the testing of an IUT using a transfer syntax where the CHOICE is visible will be extremely difficult or impossible using a test specification language which does not support information objects. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.2 Solution A: No support for information objects | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.2.1 Solution description | Provide no support for information objects. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.2.2 Solution consequences | The consequences of this solution are: • any pre-defined ASN.1 modules making use of information objects must have these information objects expanded-out before they can be used within TTCN. This process requires extra effort and is potentially error prone; • the system defined object classes would not be available; • support for certain transfer syntax's would be extremely difficult or impossible. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.3 Solution B: Support for information objects | |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.3.1 Solution description | Support the definition of information objects within TTCN. This could be achieved either by using the existing ASN.1 proformas or perhaps cleaner introducing a new proforma to allow specification of information object classes. |
2fc3ee24800832607a894caec2566ade | 101 114 | 6.2.5.3.2 Solution consequences | This solution allows direct use of pre-defined ASN.1 94 modules containing information objects, therefore saving time and effort. TR 101 114 V1.1.1 (1997-11) 37 Annex A (informative): Redefinition of ITU-T Recommendation X.680 rules for use with TTCN This appendix specifies the ASN.1 94 productions rules from ITU-T Recommendation X.680 [1] which must be redefined to allow consistent productions within TTCN as defined in ISO/IEC 9646-3 [11]. TTCN 9.5 rule 122 ASN1_Type::=Type BuiltinType::= BitStringType | BooleanType | CharacterStringType | ChoiceType | EmbeddedPDVType | EnumeratedType | ExternalType | InstanceOfType | IntegerType | NullType | ObjectClassFieldType | ObjectIdentifierType | OctetStringType | RealType | SequenceType | SequenceOfType | SetType | SetOfType | TaggedType ReferencedType ::= DefinedType | UsefulType | SelectionType | TypeFromObject | ValuesetFromObjects DefinedType ::= Externaltypereference | typereference | ParameterizedType | ParameterizedValueSetType Elements ::= SubtypeElements | ObjectSetElements | "(" ElementSetSpec ")" TTCN 9.5 rule 739 ASN1_Value ::= Value BuiltinValue ::= BitStringValue | BooleanValue | CharacterStringValue | ChoiceValue | EmbeddedPDVValue | EnumeratedValue | ExternalValue | InstanceOfValue | IntegerValue | NullValue | ObjectClassFieldValie | ObjectIdentifierValue | OctetStringValue | RealValue | SequenceValue | SequenceOfValue | SetValue | SetOfValue | TaggedValue ReferencedValue ::= TR 101 114 V1.1.1 (1997-11) 38 DefinedValue | ValueFromObject TR 101 114 V1.1.1 (1997-11) 39 Annex B (informative): ASN.1 94 syntax issues This annex considers issues associated with the defined syntax of ASN.1 B.1 Real type The syntactic checking of ASN.1 94 appears in some ways to have been weakened from the earlier versions of this language. One example of this is the real type. In ASN.1 90 the real value was explicitly defined to consist of three values Mantissa, Base and Exponent (when non-zero): NumericRealValue ::= { Mantissa, Base, Exponent } | 0 Mantissa ::= SignedNumber Base ::= 2 | 10 Exponent ::= SignedNumber Within the ASN.1 94 specification real value is defined as a sequence of named values of arbitrary length: NumericRealValue ::= 0- | SequenceValue SequenceValue ::= "{" ComponentValueList "}" | "{" "}" ComponentValueList ::= NamedValue | ComponentValueList , NamedValue This latter definition appears to provide considerably less syntactic checking allowing a value sequence of any length and also any value type. B.2 ASN.1 names The use of hyphens as separators for multi-word ASN.1 names requires name translation when ASN.1 names are used within the TTCN or SDL environments. The use of the hyphen separator within ASN.1 instead of the more usual underscore appears purely arbitrary. It would clearly be desirable to have a common multi-word separator for all these tools and avoid this unnecessary name translation. Since there are good reasons to avoid the use of the hyphen in the TTCN and SDL environments the best solution would be to change the multi-word name separator in ASN.1 from hyphen to underscore. It should be in the interest of all those involved in ASN.1 standardization to incorporate changes into the language to facilitate better interworking with other standard languages (TTCN, SDL). Better integration between these formal tools to allow seamless use of ASN.1 in all phases from specification to conformance testing can only further its appeal and use. B.3 Language issues The redefinition of DefinedValue in the ASN.1 specification for TTCN creates a unique and incompatible form of ASN.1 within TTCN. This ASN.1 dialect is formed by the coercion of TTCN production rules into the ASN.1 language specification. This situation requires tool-users to learn and distinguish various versions of the ASN.1 language and also makes it very difficult for the tool-manufacturers to develop a single ASN.1 module for use in all tools. Clearly it would be better if there was only a single Standardized specification of the ASN.1 language and this definition was used unchanged by all relevant tools. For TTCN to support this goal the redefinition of DefinedValue would have to be superseded by a new syntactically cleaner mechanism. TR 101 114 V1.1.1 (1997-11) 40 Annex C (informative): Bibliography The following material, though not specifically referenced in the body of the present document, gives supporting information. ETS 300 414 (1995): "Methods for Testing and Specification (MTS); Use of SDL in European Telecommunications Standards (Rules for testability and facilitating validation)". TR 101 114 V1.1.1 (1997-11) 41 History Document history V1.1.1 November 1997 Publication ISBN 2-7437-1813-7 Dépôt légal : Novembre 1997 |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 1 Scope | This ETSI Technical Report (TR) establishes the technical procedure for the comparative evaluation of candidate technologies for the UTRA. The UTRA includes the handling of the representative bearers as defined in UMTS 21.01 [1], i.e. Open System Interconnection (OSI) layers 1-3. It establishes the criteria based upon the requirements contained in UMTS 21.01 [1]. The primary purpose of this [report] is to facilitate the comparison of different candidates between milestones M1 and M2 of the UTRA definition procedure (Refinement and synthesis phase). It will also be used after milestone M2 (Definition phase) and in the submission of the candidate to ITU. The scope of this report is not to make the actual choice but to define how the technical evaluation will be performed. |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 2 References | This ETR incorporates by dated and undated reference, provisions from other publications. These references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this ETR only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. [1] TS 101 111 (UMTS 21.01): "Universal Mobile Telecommunication System (UMTS); Overall requirements on the radio interface(s) of the UMTS". [2] Draft new Recommendation ITU-R M.[FPLMTS.REVAL] Guidelines for evaluation of radio transmission technologies for IMT-200/FPLMTS |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 3 Abbreviations and definitions | |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 3.1 Abbreviations | For the purposes of this ETR the following Abbreviations apply. ALT Automatic Link Transfer AWGN Additive White Gaussian Noise BER Bit Error Rate CDMA Code Division Multiple Access ETE Equivalent Telephone Erlangs FDD Frequency Division Duplex FDMA Frequency Division Multiple Access FER Frame Error Rate FWA Fixed Wireless Access GSM Global System Mobile LDD Low Delay Data bearer service LCD Long Constrained Delay data bearer service UDD Unconstrained Delay Data bearer service OSI Open System Interconnection RF Radio Frequency RMS Root Mean Squared SD Standard Deviation TDD Time Division Duplex TDMA Time Division Multiple Access UMTS Universal Mobile Telecommunication System WFAU Wireless Fixed Access Unit TR 101 112 V3.2.0 (1998-04) 8 UMTS 30.03 version 3.2.0 |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 3.2 Definitions | For the purposes of this TR the following definitions apply. Traffic Capacity: (Erlangs/cell (or Erlangs/satellite spot beam)) this is the total traffic that can be supported by a single cell (or spot beam), which is part of an infinite set of cells (or large number of satellite spot beams) in a uniform two- dimensional (or three dimensional) pattern. The traffic capacity must be specified at a stated spectrum allocation, quality and grade of service, assuming an appropriate propagation model. This metric is valuable for comparing systems with identical user channel requirements. Information Capacity: (Mbits/cell (or Mbits/satellite spot beam)) this is the total number of user-channel information bits that can be supported by a single cell (or spot beam) which is part of an infinite set of cells (or large number of spot beams) in a uniform two-dimensional (or three dimensional) pattern. The information capacity must be specified at a stated spectrum allocation, quality and grade of service, assuming an appropriate propagation model. This metric is valuable for comparing systems with identical user channel requirements. Hot Spot Capacity: Number of users who may be instantaneously supported per isolated cell (or satellite spot beam) per unit spectrum. This must be specified at a stated spectrum allocation, quality and grade of service. Set of Radio Transmission Technologies: A complete combination of radio transmission technologies that encompass the transmission dependent functions of a radio system, which has potential capabilities to meet UMTS minimum requirements in one or more test environments. |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 4 Structure of the Recommendation | Clause 5 outlines the RTT considerations and identifies the transmission dependent part of the radio interface considered in the evaluation procedure. Clause 6 defines the criteria for evaluating the RTTs and clause 7 references the tests environments under which the candidate SRTTs are evaluated. The following Annexes form part of this Recommendation: Annex A: Radio Transmission Technologies Description Template Annex B: Test Environments and Deployment Models Annex C: Evaluation Methodology Annex D: Guidance on Simulations |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 5 Radio Transmission Technology considerations | This clause is same as in [2]. Within a telecommunication system (see Figure 5.1), a SRTT reflects the combination of technical choices and concepts that allow for the provision of a radio sub-system. The evaluation process for candidate UMTS RTTs will involve maximising the transmission independent aspects and minimising the differences between the remaining transmission dependent parts in the various UMTS operating environments from an implementation perspective. TR 101 112 V3.2.0 (1998-04) 9 UMTS 30.03 version 3.2.0 Figure 5.1: Radio Transmission Technologies as part of a total telecommunication system Layer 3 Layer 2 Layer 1 Network Layer containing: Call Control, Mobility Management, Radio Resource Management Legend: Transmission Transmission dependent independent Link Access Conrol Layer Medium Access Control Layer Physical Layer Figure 5.2: Example of a Layered Structure of Radio Interface Figure 5.2 presents an example of a layered structure of radio interface. As shown in Figure 5.3, the transmission dependent part of the radio interface may be considered as a set of functional blocks. It should be noted that all these functional blocks are not necessarily transmission dependent in their entirety. TR 101 112 V3.2.0 (1998-04) 10 UMTS 30.03 version 3.2.0 The functional blocks identified here are the following: - multiple access technology; - modulation technology; - channel coding and interleaving; - RF-channel parameters such as bandwidth, allocation and channel spacing; - duplexing technology; - frame structure; - physical channel structure and multiplexing. In the process of making design choices, the dependencies between the above functional blocks have to be considered. Some of the interdependencies are shown in Figure 5.3 and are further described in section 5.1. Figure 5.3: Functional Blocks and Their Interdependencies |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 5.1 Radio transmission technologies functional blocks | |
a8830263fae87d2bee9405dc0aea0e60 | 101 112 | 5.1.1 Multiple access technology | The choice of the multiple access technology has major impact on the design of the radio interface. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.