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Lakshmanan, M.
- Design of Enhanced Cross-Layer Handoff Management Protocol for Next Generation Wireless Systems
Authors
1 School of Electrical Sciences of VIT University, Vellore–632014, Tamil Nadu, IN
2 School of Electrical Sciences of VIT University, Vellore – 632014, Tamil Nadu, IN
Source
Networking and Communication Engineering, Vol 1, No 5 (2009), Pagination: 193-199Abstract
In Next-generation wireless systems (NGWS), different wireless network is integrated and each of the networks is optimized for some specific services to provide ubiquitous communications to the mobile users. It is an important and challenging issue to support seamless handoff management in this integrated architecture. This paper deals about design of enhanced cross-layer handoff management protocol HMP) and is developed to support seamless intra and intersystem handoff management in NGWS. Cross-layer handoff management protocol uses mobile’s speed and handoff signaling delay information to enhance the handoff performance of Mobile IP in terms of probability of false handoff initiation and probability of handoff failure. Firt, thehandoff performance of Mobile IP is analyzed with respect to its sensitivity to the link layer (Layer 2) and network layer (Layer 3)parameters. Then enhanced cross-layer handoff management architecture is developed using the insights learnt from the analysis.Finally, simulation results show that CHMP significantly enhances the performance of both intra and intersystem handoffs independent of mobile terminal velocity and network handoff latency.
Keywords
HMP, Link Layer, Mobile IP, Network Layer and NGWS.
- Frequency Domain Equalization for Single Carrier Wireless Systems
Authors
1 School of Electrical Sciences of VIT University, Vellore–632014, TamilNadu, IN
Source
Networking and Communication Engineering, Vol 1, No 4 (2009), Pagination: 177-183Abstract
Computational complexity and error propagation phenomenon are important drawbacks of existing Decision Feedback Equalizers (DFE) for dispersive channels. A new Iterative Block DFE (IBDFE) is considered where the equalization is performed iteratively on blocks of received signal in the frequency domain i.e. both signal processing and filter design are in frequency domain. Thus computational complexity is reduced and error propagation is limited to one block. The feed forward and feedback filters of DFE are designed with the minimization of Mean Square Error (MSE) at detector input as the parameter for effective detection. Two design methods have been solved and simulated for a Rayleigh fading channel. Channel is assumed to be time in-variant during one block of data (128 symbols) transmission. In the first method, the hard detected data are used as the input to the feedback, and filters are designed according to the correlation between detected and transmitted data. In the second method, the feedback signal is directly designed from soft detection of the equalized signal at the previous iteration. Estimates of the parameters involved in the FF and FB filters are also solved and used to evaluate the filter coefficients. From simulation, it was found that the IBDFE as claimed in the research literature performs better than the time domain DFE.