-Based on an empirical study, this paper makes the following key contributions: Firstly, the results show that for ON-OFF traffic, RIO is better than WRED in protecting packets marked for treatment with lower drop precedence. Secondly, for shortlived flows, RIO achieves higher transactional rates than WRED. Thirdly, for bulk transfer, RIO and WRED achieve comparable long-term throughput. Finally, this paper also reports the results of experiments with 3 different models for setting of WRED and RIO parameters. We recommend the "staggered" model as best suited to achieve the requirements of the AF PHB.

To cater the ever-increasing demand of wireless high-speed data access and mobile users, one of the potential enablers toward the sustainable improved network capacity is the network densification at different layers of the radio access system. In this article, a possible solution to achieve a spectrally efficient, ultradense network (UDN) for cellular communication is analyzed. In particular, the performance of the generalized M-ary quadrature amplitude modulation (M-QAM) scheme for multiantenna cooperative decode-and-forward (DF) system over two-wave with diffuse power (TWDP) fading is presented. The TWDP fading is evaluated using the moment generating function (MGF) based approach on spectral efficient QAM transmission. In this article, novel closed-form expressions for the exact average symbol error rate (ASER) for the generalized rectangular-QAM (R-QAM) and square-QAM (S-QAM) schemes are presented. The obtained expressions are in the form of Appell's and Laureicella's confluent hypergeometric function which can be evaluated mathematically either in the series or the integral-form. Further, the asymptotic analysis is also presented for the considered system to get better insights into the system.The analytical results derived are corroborated by simulations to validate the accuracy of the analysis.

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Abstract-This paper evaluates the suitability of Backward Explicit Congestion Notification (BECN) for IP networks. The BECN mechanism has previously been used in non-IP networks, but there has been limited experimental investigation into the application of the BECN scheme as congestion control mechanism in IP networks. In this paper, we consider an enhanced algorithm for BECN which uses Internet Control Message Protocol (ICMP) Source Quenches for backward congestion notification in IP networks and undertake comparative performance evaluation of Random Early Detection (RED), Explicit Congestion Notification (ECN) and our enhanced BECN mechanism using both longlived TCP bulk transfers and short-lived webtraffic workloads. Our results show that for webtraffic workloads, BECN offers only slight improvement in transfer delay while average goodput for bulk transfers is no worse than that of ECN. For paths that have a high bandwidth delay product our results show that not only can BECN offer significant improvement in average goodput for bulk transfers over the ECN mechanism, but packet drops and transfer delay for short-lived webtraffic connections are also comparatively reduced. Additional observations show that on such paths TCP (NewReno) with RED can offer higher goodput for bulk transfers compared to ECN.We investigate the overhead due to Source Quenches in a BECN capable network and find that for scenarios considered in this paper it does not significantly impact performance of BECN.