High performing multimedia transmission approach based on QoS support and admission control over IEEE 802.11e networks

Hybrid coordination function controlled channel access (HCCA) is a medium to enhance quality of service (QoS) via the IEEE 802.11e standard. The main limitation of HCAA is that it is only efficient for constant bit rate (CBR) applications. This is due to the nature of its scheduler that allocates transmission opportunities (TXOPs) based on traffic stream (TS) specifications (TSPECs) that are determined during the traffic setup time. Variable bit rate (VBR) traffics used in HCCA have nondeterministic profile, making it not optimally and efficiently supported by HCCA. The result of this inefficiency is a deterioration of the transmission performance of multimedia data as well as a drop in the number of served QoS video traffics. We propose a novel approach to deal with this issue, which is the feedback‐based admission control unit (FACU). FACU works by optimizing the usage of extra bandwidth to ensure optimal transmission performance of multimedia data. FACU achieves this by exploiting piggybacked information concerning sequential video frames in order to accurately assign the TXOP. The proposed approach is evaluated by utilizing various video sequences. It is demonstrated that FACU maximizes the overall number of video streams and optimizes the overall usage of the network without having any adverse effects on the QoS constraints determined.     

Phenylpropanolamine HCl Microcapsules: Preparation and release studies

Microcapsules of phenylpropanolamine HCL were prepared by three techniques, viz. coacervation-phase separation, air suspension, and pan coating, using different polymers and/or waxes as wall-forming materials.

Formulations showed reasonable dissolution behaviour, viz. microcapsules prepared by air suspension with polymer level of 20% polyvinyl acetate copolymer (PVAC) associated with 40% carnauba wax (II) and microcapsules prepared by pan coating with polymer level of 25% Rodopace^R (III), were evaluated for their absorption rates by demonstrating their toxicities compared to pure grug (I) by the LD₅₀ method. Toxicity assessment showed close agreement between the increase in lethal dose and the decrease in dissolution rate and revealed that Formula III has more prolonged action than Formulae II and I.     

Enhancement of the Traffic Differentiation Architecture for WBAN Based on IEEE 802.15.4

In the healthcare domain, Wireless Body Area Network has emerged as a vital technology that is capable of providing better methods to diagnose various hazardous diseases. The CANet projet is a project that proposes alternative monitoring solutions. This paper studies the possibility of transmitting different types of information through an IEEE 802.15.4 MAC layer that not supports the transmission of heterogeneous information. We have proposed an extension to the MAC layer which makes possible the transmission of various information types. This solution designed by “diffrentiation layer” uses a purge function to ensure the use of CAP and CFP by the same node in the same superframe and allows the differentiation between several information. Our results show that our solution is reliable under worst-case.