In this paper, my aim is to provide an overview of the key challenges arising from Het Nets, Relay Nodes, SON, RRM, Co-MIMO, Cognitive Radio Network, DAS and highlight their importance. Recent research mainly concentrates on the aspect of interference mitigation, radio resource utilization, fairness, complexity and QoS. Improve the coverage as well as the capacity with high speed achieved by HE...

The provision of high capacity, low cost and reliable wireless multimedia communication for bursty packet traffic (as well as voice and delay constrained streaming traffic) continues to be a challenging aspect of future wireless communications systems. In this sense, structured and ad-hoc multihop networks and intelligent relaying are expected to play a significant role in 4G wireless communica...

Recombinant granulocyte/macrophage colony-stimulating factors (rGM-CSF) of mouse and human origins activated macrophages of the homologous species to inhibit the replication of the protozoan parasite T. cruzi. Activation could be induced with 10-100 ng/ml of rMu-GM-CSF, whether it was added before or after uptake of the parasite, in either adherent or suspension cultures. However, the degree of...

We consider the problem of adaptive cell sectorization i n a CDMA system. Specifically, given the user distribution in a cell, we investigate the two problems of how to appropriately sectorize the cell such that we minimize the total received power and the total transmit power spent by all the users, in both cases, while giving each user acceptable quality of service. The optimum arrangement eq...

The capacity of multiple-input multiple-output (MIMO) systems employing reconfigurable apertures (RECAPs) is carefully analyzed with a realistic thermal noise model for three different power constraints: average receive signal-to-noise ratio (SNR), maximum effective isotropic radiated power (EIRP), and average transmit power. Performance is studied not only for a noise-limited single link, but ...

Network coding technique increases wireless network communication efficiency. Wireless multihop relay network has been shown to achieve capacity gain over conventional single-hop wireless networks. Hybrid wireless relay networks integrate multihop ad hoc relay and infrastructure base stations to achieve better wireless network performance. Applying the promising network coding technique to hybr...

One of the biggest drawbacks of the wireless environment is the limited bandwidth. However, the users sharing this limited bandwidth have been increasing considerably. SDMA technique which entails using directional antennas allows to increase the capacity of a wireless network by separating users in the medium. In this paper, it has been presented how the capacity can be enhanced while the mean...

Originally developed to be used in GSM by the Europe Telecommunications Standards Institute (ETSI), the AMR speech codec [TS 26.071] was approved within the 3GPP forum in 1999 to be mandatory for circuitand packet-switched speech in UMTS networks. An AMR speech codec adapts the error protection level to the local radio channel and traffic conditions so that it always selects the optimum channel...

The wide-band code division multiple access (WCDMA) based 3G and beyond cellular mobile wireless networks are expected to provide a diverse range of multimedia services to mobile users with guaranteed quality of service (QoS). To serve diverse quality of service requirements of these networks it necessitates new radio resource management strategies for effective utilization of network resources...

The capacity of an ad hoc wireless network is determined by its topology and the resulting signal-to-interference ratio experienced by the various wireless links that interconnect different nodes. The Shannon capacity theorem is the fundamental result that relates the link bandwidth and the signal-tointerference ratio (SIR) experienced by a link. The link capacity in turn defines the upper boun...