The objective of this chapter is twofold: from one side, techniques and methodologies of the failure science are introduced for each three development phases; on the other side, some practical examples of these methodologies are shown for the case of wireless systems. During phase 1 the reliability of the entire system can be estimated in a general way thanks to failure analysis predictive tools based on failure probability data/models available for each system component (Reliability Predictive Modeling, RPM). The resulting model can be semi-empirical and, as such, it will be based on a huge amount of data. The Military Handbook is a standard example of this type of predictive methodology. Alternatively (or in addiction), it is possible to take into consideration the physical knowledge of the failure mechanisms that are always supposed to be present. The resulting models allow calculating the MTTF in a more accurate way as a function of some basic physical quantities involved in the failure mechanisms. The knowledge of both models is fundamental to address the first project phases and provides accurate estimates of the system reliability. In addition, the failure models allow selecting the methodologies, the criteria and the characteristic parameters for the accelerated tests performed during design and validation phases. Examples of instruments used during phase 1 and related to reliability prediction and modelling will be discussed in section 2 and will consider electronic devices such as MESFET and, semiconductor memories, and some physical mechanisms such as corrosion and ionic migration. The evaluation of the MTTF will also be addressed. Phases 2 and 3 will be discussed in a more general way in sections 3 and 4, where the techniques used in these phases will be applied to a common mobile phone part: the vibrating motor. Issues related to phase 4 will be tackled in section 5 regarding the burn-in, the fault tolerance, the relationship between defects, yield and reliability and the use of redundancy in memories.
Reliability in Wireless Systems
CHIMENTON, Andrea;OLIVO, Piero
2008
Abstract
The objective of this chapter is twofold: from one side, techniques and methodologies of the failure science are introduced for each three development phases; on the other side, some practical examples of these methodologies are shown for the case of wireless systems. During phase 1 the reliability of the entire system can be estimated in a general way thanks to failure analysis predictive tools based on failure probability data/models available for each system component (Reliability Predictive Modeling, RPM). The resulting model can be semi-empirical and, as such, it will be based on a huge amount of data. The Military Handbook is a standard example of this type of predictive methodology. Alternatively (or in addiction), it is possible to take into consideration the physical knowledge of the failure mechanisms that are always supposed to be present. The resulting models allow calculating the MTTF in a more accurate way as a function of some basic physical quantities involved in the failure mechanisms. The knowledge of both models is fundamental to address the first project phases and provides accurate estimates of the system reliability. In addition, the failure models allow selecting the methodologies, the criteria and the characteristic parameters for the accelerated tests performed during design and validation phases. Examples of instruments used during phase 1 and related to reliability prediction and modelling will be discussed in section 2 and will consider electronic devices such as MESFET and, semiconductor memories, and some physical mechanisms such as corrosion and ionic migration. The evaluation of the MTTF will also be addressed. Phases 2 and 3 will be discussed in a more general way in sections 3 and 4, where the techniques used in these phases will be applied to a common mobile phone part: the vibrating motor. Issues related to phase 4 will be tackled in section 5 regarding the burn-in, the fault tolerance, the relationship between defects, yield and reliability and the use of redundancy in memories.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
