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Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (EUTRAN) deals with high uplink and downlink throughput. The Proportional Fair (PF) Medium Access Control (MAC) scheduler offered a good balance between allocated resources and fairness among the User Equipment (UE) in comparison with other schedulers. In the PF scheduler, at each cycle of resource allocation, a feedback mechanism ensures that operational resource requirements are met while maintaining a degree of fairness among the UE. We analyze the effect of feedback Transmission Time Interval (TTI) delay on two typical EUTRAN networks, in terms of Key Performance Indicators (KPIs). One network is referred to as EUTRAN LTE and the other as EUTRAN LTE-A, which fulfils high throughput requirement. We evaluate the performance of the PF MAC scheduler for both networks under varying feedback delay in TTI. Simulated results show that the delay in TTI affects the performance of resource allocation in terms of throughput, fairness, and spectral efficiency. Feedback delay improves network performance by compensating effect of imperfect channel condition.

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Joining of dissimilar materials is difficult and challenging. Trend towards replacement of high density material (HDM) by low density material (LDM) is gaining importance in automotive industries. In the present work, friction stir welding (FSW) of high strength dissimilar materials i.e. aluminium alloy AA7475-T761 and stainless steel AISI 304 was conducted. The mechanical properties and microstructure of butt joint were investigated on using Taguchi L8 orthogonal array (OA). Different combinations of FSW parameters were used to obtain the maximum value of UTS. It was observed that most dominating parameter affecting UTS is tool rotational speed, contributing 42.19%, followed by traverse speed with 38.96% and shoulder diameter with 12.60%. The maximum UTS was observed 75.22% of base material AA 7475 (452MPa) under the optimum combination of parameters; tool rotational speed at 450 rpm, traverse speed 63 mm/min and shoulder diameter 14 mm. The microstructure of the resulted efficient joint shows appreciable variation in grain sizes in different zones and the micro hardness was found maximum in SZ on the retreating side.