Open Topics

Vol. 67, n° 11-12, November-December 2012
Content available on Springerlink

An AHP-based resource management scheme for CRRM in heterogeneous wireless networks

Choongyong Shin1, Jinsung Cho1, Jeong Geun Kim1 and Ben Lee2
(1) Kyung Hee University, Korea
(2) Oregon State University, USA

Abstract In a heterogeneous wireless environment, a variety of Radio Access Technologies (RATs) coexist. Since the number of RATs is anticipated to increase in the near future, it is desirable to have radio and network resources managed in a cooperative manner using the Common Radio Resource Management (CRRM) strategy. In order to make RAT-specific radio resources manageable in CRRM, this paper proposes the Analytical Hierarchy Process (AHP) based resource management scheme that efficiently allocates resources among heterogeneous wireless networks. The proposed AHP-based method is simple and flexible enough to be used in any network environment and can consider a multitude of decision factors. In addition, the proposed scheme uses a radio bandwidth model, which properly reflects transmission rates under given channel conditions, as the actual radio resources to be allocated. The model considers the AMC (Adaptive Modulation and Coding) scheme that is widely used in current broadband wireless access technologies, and thus, packet service characteristics, such as response time, can be analyzed. This is in contrast to existing work that focuses only on circuit service characteristics (e.g., blocking probability). The effectiveness and flexibility of the proposed method are demonstrated by implementing a number of existing methods and performing extensive simulation study on several different scenarios.

Keywords Heterogeneous network – Common radio resource management (CRRM) – Radio bandwidth model – AHP

An autonomic mobility management solution for the future wireless Internet

Meriem Abid1  , Daniel F. Macedo2  , Javier Rubio-Loyola3  and Guy Pujolle1
(1) Université Pierre et Marie Curie, UPMC, France
(2) Universidade Federal de Minas Gerais, UFMG, Brazil
(3) CINVESTAV Tamaulipas, Mexico

Abstract The recent development of a myriad of heterogeneous wireless technologies that share the same core IP is driving the mobility as a key issue for the future wireless Internet. One of the critical challenges is to support uninterrupted and seamless multimedia services while on the move. This article focuses on mobility management in the future Internet regarding a solution proposed in the Autonomic Internet (AutoI) project. Our mobility management solution aims at enhancing user mobility experience and enabling adaptability and context awareness in the future wireless Internet. This is achieved through the use of more adequate information exploited by a utility-based mobility decision approach as well as a hysteresis margin to preserve decision stability. The proposed solution is discussed and experimental validations are performed to evaluate its impact on real-world scenarios. The proposed solution has been demonstrated to be effective in providing seamless user experience even with frequent handovers. Further, the use of the hysteresis-based mobility decision solution has been effective to reduce the number of handovers, without precluding the quality of connections.

Keywords Adaptability – Mobility – Autonomic – Decision – Management – Context awareness

Reduced complexity decoding of convolutional codes based on the M-algorithm and the minimal trellis

Richard Demo Souza1  , Cecilio Pimentel2  and Daiana Nascimento Muniz1
(1) Federal University of Technology—Paraná (UTFPR), Brazil
(2) Federal University of Pernambuco (UFPE), Brazil

Abstract In this paper, we propose three new sub-optimum, reduced complexity decoding algorithms for convolutional codes. The algorithms are based on the minimal trellis representation for the convolutional code and on the M-algorithm. Since the minimal trellis has a periodically time-varying state profile, each algorithm has a different strategy to select the number of surviving states in each trellis depth. We analyse both the computational complexity, in terms of arithmetic operations, and the bit error rate performance of the proposed algorithms over the additive white Gaussian noise channel. Results demonstrate that considerable complexity reductions can be obtained at the cost of a small loss in the performance, as compared to the Viterbi decoder.

Keywords Convolutional codes – Minimum trellis – M-algorithm – Viterbi decoding

A pairing-free identity-based authenticated group key agreement protocol for imbalanced mobile networks

SK Hafizul Islam1  and G. P. Biswas1
(1) Indian School of Mines, Dhanbad, Jharkhand, India

Abstract The secure and reliable group communication gains popularity in imbalanced mobile networks due to the increase demand of the group-oriented applications such as teleconferences, collaborative workspaces, etc. For acquiring the group security objectives, many authenticated group key agreement (AGKA) protocols exploiting the public key infrastructure have been proposed, which require additional processing and storage space for validation of the public keys and the certificates. In addition, the most of the AGKA protocols are implemented using bilinear pairing and a map-to-point (MTP) hash function. The relative computation cost of the bilinear pairing is approximately two to three times more than the elliptic curve point multiplication (ECPM) and the MTP function has higher computation cost than an ECPM. Due to the limitation of communication bandwidth, computation ability, and storage space of the low-power mobile devices, these protocols are not suitable especially for insecure imbalanced mobile networks. To cope with the aforementioned problems, in this paper, we proposed a pairing-free identity-based authenticated group key agreement protocol using elliptic curve cryptosystem. It is found that the proposed protocol, compared with the related protocols, not only improves the computational efficiencies, but also enhances the security features.

Keywords Identity-based cryptosystem – Elliptic curve cryptography – Public key infrastructure – Imbalanced mobile network – Authenticated group key

Some experimental investigations in the WiMAX band and comparison of propagation models in mixed urban environments of Western India

Chhaya Dalela1 , M. V. S. N. Prasad2  and P. K. Dalela3
(1) JSS Academy of Technical Education, Noida, India
(2) CSIR National Physical Laboratory, New Delhi, India
(3) C-DOT, New Delhi, India

Abstract This paper presents the analysis of measurements taken at 2.3 GHz in the mixed urban environments of Western India for 17 WiMAX base stations. Coverage predictions using various models and their comparison with observed data have been carried out. Measured path loss is compared with the theoretical path loss values estimated by COST-231 Hata model, the SUI model, the ECC model, and ITU-R (P.1411-1) model. This investigation is essential to provide last mile broadband wireless access, before deploying WiMAX. Path loss exponents, mean errors, and standard deviations of all the prediction methods were deduced and suitable models for path loss prediction methods were identified.

Keywords Path loss – Path loss exponent – Propagation model – WiMAX – Terrain

Rain-induced attenuation for Ku-band satellite communications in the west coast of Peninsular Malaysia, Penang

Renuka Nalinggam1, Widad Ismail2 and J. S. Mandeep3, 4
(1) AIMST University, Kedah Darul Aman, Malaysia
(2) Universiti Sains Malaysia, Pulau Pinang, Malaysia
(3) Universiti Kebangsaan Malaysia, Selangor, Malaysia
(4) Universiti Kebangsaan Malaysia, Selangor Darul Ehsan, Malaysia

Abstract Accurate rainfall rate is important for predicting rain attenuation over a satellite link. Raindrops are able to take in, spread out, and change the polarization of satellite signals that pass through the atmosphere of the earth, especially in equatorial regions like Malaysia where heavy rainfall normally occurs. Satellite communications system network operating at Ku-Band will experience rain fade due to absorption and scattering of signal. This paper aims to discuss the range of effects of rain on the transmission of electromagnetic signal and to determine the significance of rainfall rate in the prediction of rain attenuation based on measurements carried out in the northern region of Peninsular Malaysia (Penang). At 0.01% of time, 140 mm/h and 22 dB of rain rate and attenuation were observed, respectively.

Keywords Rain rate – Rain attenuation – Tropical region

EBvN: efficient BvN in multi-fiber/multi-wavelength overlaid-star optical networks

Akbar Ghaffarpour Rahbar1
(1) Sahand University of Technology, Tabriz, Iran

Abstract Overlaid-star networks with reservation-based scheduling could be appropriate networks for metro areas. The Birkhoff–von Neumann (BvN) scheduling could be used at the core nodes of an overlaid network to schedule lossless traffic transmission among edge nodes. The common method is to schedule traffic separately for each wavelength channel, called separated BvN (SBvN) scheduling in this paper. However, SBvN cannot schedule all traffic demands, especially at high-traffic loads. In this paper, the BvN scheduling procedure is modified to efficiently schedule traffic in overlaid-star networks with multi-fiber/multi-wavelength architecture, called efficient BvN (EBvN). Instead of using one processor to schedule traffic on one wavelength channel in each core node, the proposed EBvN technique uses only one processor to schedule all traffic demands on all fibers/wavelength channels at the same time. Performance evaluation results under both uniform and non-uniform traffic distributions show that more traffic demands can be scheduled under EBvN compared with SBvN. In addition, the scheduling speed of EBvN is mostly faster than SBvN. Finally, EBvN can provide bound on the maximum scheduling time of EBvN. As a trade-off between scheduling time and residual traffic, EBvN with filling empty cells (EBvN_FEC) is proposed that can reduce residual traffic, but at the expense of slightly increasing scheduling time. EBvN_FEC is more effective than EBvN under non-uniform traffic distribution.

Keywords Overlaid-star metro networks – BvN scheduling – Multi-fiber/multi-wavelength optical network – Reduced complexity core nodes

Capacity analysis of distributed antenna systems in MIMO Nakagami fading multicell environment

Xiangbin Yu1, 3, Ying Yang1, 2, Mingqi Li2 and Ming Chen3
(1) Nanjing University of Aeronautics and Astronautics, China
(2) Chinese Academic of Science, Shanghai, China
(3) Southeast University, Nanjing, China

Abstract In this paper, the downlink capacity analysis of distributed antenna systems (DAS) with multiple receive antennas in Nakagami-m fading multicell environment is presented. According to the performance analysis, and using mathematical manipulation, we derive the probability density function (PDF) of the effective signal to interference plus noise ratio of the system. Based on the obtained PDF, an exact closed-form expression of DAS capacity is derived. This expression includes the existing capacity expression as a special case, and avoids the error in the latter. Thus, it can provide good theoretical performance evaluation for downlink DAS. Computer simulation shows that the theoretical analysis is in good agreement with simulation result. Moreover, the increase of receive antenna and/or Nakagami fading parameter m can improve the capacity effectively.
Keywords Capacity analysisDistributed antenna systemsMultiple receives antennasNakagami fadingMulticell environment