38 research outputs found
On the Effective Capacity of Two-Hop Communication Systems
In this paper, two-hop communication between a source and a destination with
the aid of an intermediate relay node is considered. Both the source and
intermediate relay node are assumed to operate under statistical quality of
service (QoS) constraints imposed as limitations on the buffer overflow
probabilities. It is further assumed that the nodes send the information at
fixed power levels and have perfect channel side information. In this scenario,
the maximum constant arrival rates that can be supported by this two-hop link
are characterized by finding the effective capacity. Through this analysis, the
impact upon the throughput of having buffer constraints at the source and
intermediate-hop nodes is identified.Comment: submitted to ICC 201
Delay-aware and power-efficient resource allocation in virtualized wireless networks
This paper proposes a delay-aware resource provisioning policy for virtualized wireless networks (VWNs) to minimize the total average transmit power while holding the minimum required average rate of each slice and maximum average packet transmission delay for each user. The proposed cross-layer optimization problem is inherently non-convex and has high computational complexity. To develop an efficient solution, we first transform cross-layer dependent constraints into physical layer dependent ones. Afterwards, we apply different convexification techniques based on variable transformations and relaxations, and propose an iterative algorithm to reach
the optimal solution. Simulation results illustrate the effects of the required average packet transmission delay and minimum average slice rate on the total transmission power in VWN
A Sensing Error Aware MAC Protocol for Cognitive Radio Networks
Cognitive radios (CR) are intelligent radio devices that can sense the radio
environment and adapt to changes in the radio environment. Spectrum sensing and
spectrum access are the two key CR functions. In this paper, we present a
spectrum sensing error aware MAC protocol for a CR network collocated with
multiple primary networks. We explicitly consider both types of sensing errors
in the CR MAC design, since such errors are inevitable for practical spectrum
sensors and more important, such errors could have significant impact on the
performance of the CR MAC protocol. Two spectrum sensing polices are presented,
with which secondary users collaboratively sense the licensed channels. The
sensing policies are then incorporated into p-Persistent CSMA to coordinate
opportunistic spectrum access for CR network users. We present an analysis of
the interference and throughput performance of the proposed CR MAC, and find
the analysis highly accurate in our simulation studies. The proposed sensing
error aware CR MAC protocol outperforms two existing approaches with
considerable margins in our simulations, which justify the importance of
considering spectrum sensing errors in CR MAC design.Comment: 21 page, technical repor