A new approach for performance analysis of orthogonal space–time block coding systems with antenna selection is presented. Antenna selection has been performed at the transmitter and/or at the receiver sides. Closed‐form expressions are derived for the approximate average bit error rate (BER) of the considered system for M ‐ary quadrature amplitude modulation and phase‐shift keying schemes. Different from other approaches presented in the literature, analytical expressions are derived for the average signal‐to‐noise ratio (SNR) gain obtained from each antenna selection scheme, and then using those SNR gains closed‐form expressions are obtained for the approximate average BER performance. The system performances of several forms of the presented scheme are evaluated and compared. It is shown that the results obtained from the mathematical expressions match closely with simulation results.

This paper, presents evaluation and analysis of the performance for multiple-input multiple-output (MIMO) schemes in the 3GPP long term evolution (LTE) system. Three performance metrics are considered for the analysis and evaluation, namely, average BER, average channel capacity and average throughput of the system for two different MIMO schemes as defined in LTE. Using the numerical results obtained from the mathematical expressions derived in the paper, we compare the presented schemes and show their significant advantages. Monte-Carlo simulation results of the LTE system are also provided to verify the accuracy of the mathematical analysis. The results for the average throughput of the considered MIMO schemes in LTE are presented for the un-coded case as well as for the coded-case in practical LTE scenarios. In addition, for the sake of comparison, the theoretical capacity limit of the system is also shown.

In this paper, a performance analysis is presented for space-frequency block coded orthogonal frequency divi sion multiplexing (SFBC-OFDM) and Frequency Switched Transmit Diversity OFDM (FSTD-OFDM) schemes in the 3GPP Long Term Evolution (LTE) system over MIMO fading channels. Analytical expressions for the average BER, average channe l capacity and the average throughput of the system are derive d for two different MIMO schemes, SFBC-OFDM and FSTD-OFDM, defined in LTE, and are evaluated numerically. Monte-Carlo simulation results are also provided to verify the accuracyof the mathematical analysis. It is shown that the results obta ined from Monte-Carlo simulations match closely with those obtained from the derived mathematical formulas. KeywordsPerformance Analysis, MIMO, LTE, M-QAM Modulation, Capacity, Throughput. I. I NTRODUCTION To increase the capacity and speed of wireless communication systems, a new wireless data networks has been emerged and has been standardized by the 3rd Generation Partnership Project ( 3GPP). This new standard is a natural evolution to the existing second ( 2G) and third (3G) generation wireless networks in order to respond to the growing demand in terms of data rates and speed and marketed as 4G Long Term Evolution (LTE). In LTE, data throughput and the speed of wireless data are increased by using a combination of new methods and technologies like Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input MultipleOutput (MIMO) techniques. In the downlink, LTE transmission is based on Orthogonal Frequency Division Multiple Access (OFDMA), known as a technique for encoding digital data on multiple carrier fre quencies. It was shown that OFDMA is an efficient technique to improve the spectral efficiency of wireless systems. By converting the wide-band frequency selective channel into a set of several flat fading subchannels, OFDM technique becomes more resistant to frequency selective fading than sin gle carrier systems. As OFDM signals are in time and frequency domain, they allow adding frequency domain scheduling to time domain scheduling. In LTE, for a given transmission power, the system data throughput and the coverage area can be optimized by employing Adaptive Modulation and Coding (AMC) techniques. The role of a user scheduler at the transmitter side is to assign the data rate for each user according to the channel conditions from the serving cell, t he interference level from other cells, and the noise level at t he receiver side. In LTE standard, the use of MIMO has been considered as an essential technique in order to achieve the target in term s of data throughput and reliability. MIMO is known to be a very powerful technique to improve the system performance o f wireless communication systems. The diversity and multipl exing modes are the two main modes of operation of multiple antennas systems. The principle of diversity mode is based on transmitting the same signal over multiple antennas and hence to improve the reliability of the system by a diversity gain. In this mode, the mapping function of transmit symbols used at the transmit antennas is called Space Time Block Coding (STBC). On the other hand, multiplexing mode uses two or more different spatial streams and sends them through two different antennas, consequently, the data rate can be improved. In [1] an analysis is performed for evaluating the average bi t error rate (BER) of MIMO schemes in LTE systems employing the classical M-ary quadrature amplitude modulation (MQAM) scheme. In this paper, we provide more details about the system model and about the considered transmit diversit y schemes in LTE and we extend the results in [1] and in addition to the average BER analysis, we present the average capacity analysis as well as the average throughput analysi s for two different MIMO schemes as defined in LTE. Then, the results obtained from analytical formulas are provided , showing the performance of the considered schemes. From those results one can simply compare the benefits of using considered MIMO schemes. In addition, the results obtained from Monte-Carlo simulations are also provided to verify th e accuracy of the analysis for each performance metric. To study the performance of LTE systems a MATLAB based downlink physical layer simulator for Link Level Simulatio n (LLS) has been developed in [2], [3]. A System Level Simulation of the Simulator is also available [4]. The goal of developing the LTE simulator was to facilitate comparison with the works of different research groups and it is publicl y available for free under academic non-commercial use licen se [3]. The main features of the simulator are adaptive coding 2 International Journal on Advances in Networks and Services, vol 7 no 1 & 2, year 2014, http://www.iariajournals.org/networks_and_services/ 2014, © Copyright by authors, Published under agreement with IARIA www.iaria.org and modulation, MIMO transmission and scheduling. As the simulator includes many physical layer features, it can be used for different applications in research [4]. In [5], the simulator was used to study the channel estimation of OFDM systems and the performance evaluation of a fast fading channel estimator was presented. In [6] and [7], a method for calculating the Precoding Matrix Indicator (PMI), the Rank Indicator (RI), and the Channel Quality Indicator (CQI) wer e studied and analyzed with the simulator. In this paper, analyses of the performance for two transmit diversity schemes, known as Space Frequency Block Coding (SFBC) and Frequency Switched Transmit Diversity (FSTD) MIMO schemes in LTE system, are presented for different performance metrics. Those performance metrics are the average BER, the average capacity and the average throughput. The average BER results obtained from the analysis are then compared to the results of Monte-Carlo simulation using the Link Level LTE simulator [2], [3]. The remainder of this paper is organized as follows. In Section II, we present the system model used in the paper. In Section III, we present performance analyses for the averag e BER, the average capacity and the average throughput of SFBC and FSTD MIMO schemes. The numerical and simulation results and discussions are presented in Section IV . Finally, Section V concludes the paper. II. SYSTEM MODEL In this section, the structure of the OFDM LTE signal and LTE transmit diversity schemes are described. However, mor e details can be found in [8]. The OFDM signal has a time and a frequency domains. In the time domain, the LTE signal is composed of successive frames. Each frame has a duration of Tframe= 10 msec. Each frame is divided into10 subframes with equal length of1 msec. Each subframe consists of two equal length time-slots with a time duration of Tslot = 0.5 msec. For a normal cyclic prefix length, each time-slot consists of Ns = 7 OFDM symbols. In the frequency domain, the OFDM technique converts the LTE wideband signal into several narrowband signals. Each narrowband signal is transmi tted on one subcarrier frequency. In LTE, the spacing between subcarriers is fixed to 15 KHz. Twelves adjacent subcarriers, occupying a total of 180 KHz, of one slot forms the so-called Resource Block (RB). The number of Resource Blocks in an LTE slot depends on the allowed system bandwidth. The minimum number of RB is equal to 6 corresponding to 1.4 MHz system bandwidth. For 20 MHz system bandwidth (Maximum Allowed bandwidth in LTE) the number of RB is equal to 100. In a MIMO system with MR receive antennas and MT transmit antennas, the relation between the received and the transmitted signals o n subcarrier frequencyk (k ∈ 1, · · · ,K), at sampling instant time n (n ∈ 1, · · · , N ) is given by yk,n = Hk,nxk,n + nk,n (1) whereyk,n ∈ CMR×1 is the received vector, Hk,n ∈ CMR×MT represents the channel matrix on subcarrier k at instant time n, xk,n ∈ CMR×1 is the transmit symbol vector and nk,n ∼ CN (0, σ n.I) is a white, complex valued Gaussian noise vector with varianceσ n. Assuming perfect channel estimation, the channel matrix and noise variance are considered to be known at the receiver . A linear equalizer filter given by a matrix Fk,n ∈ CMR×MR is applied on the received symbol vector yk,n to determine the post-equalization symbol vector rk,n as follows [7] rk,n = Fk,nyk,n = Fk,nHk,nxk,n + Fk,nnk,n. (2) The Zero Forcing (ZF) or Minimum Mean Square Error (MMSE) design criterion [9] are typically used for the linea r receiver and the input signal vector is normalized to unit power. In MIMO-OFDM systems, the key factor of link error prediction and performances is the signal to noise ratio (SN R) which represents the measurement for the channel quality information. In this study, the SNR is defined by γk,n = γ NT ‖Hk,n‖2F (3) whereγ = Es/N0 is the average SNR per symbol and ‖.‖F is the squared Frobenius norm of a matrix. A. LTE Frame Structure Two types of LTE frame structures are defined depending on the duplexing mode of the transmission. Two duplexing methods are defined in LTE, namely Time Division Duplex (TDD) and Frequency Division Duplex (FDD). In the FDD mode, the downlink path (DL), from the eNodeB to user equipment (UE), and the uplink path (UL), from the UE to eNodeB, operate on different carrier frequencies. In the TD D mode, the downlink and the uplink paths operate on the same carrier frequency but in different time slots. In other word , in FDD, the downlink and uplink transmissions are separated in the frequency domain, whereas in TDD the downlink and uplink transmissions are separated in the time domain. Type 1 frame structure of LTE is associated with the FDD duplexing mode whereas Type 2 frame structure of LTE is associated with the TDD duplexing mode. For both types of LTE frame structures, the DL and UL transmissions in LTE systems are arranged into radio frames. The duration of a radio frame is fixed at 10msec. The radio frame is comprised of ten 1 msec

In this paper, a Bit Error Rate (BER) analysis is presented for Multiple-Input Multiple-Output (MIMO) sche mes in the 3GPP Long Term Evolution (LTE) system. Analytical expressions for the average BER of the system are derived ove r flat Rayleigh fading channels for two different MIMO schemes as defined in LTE, assuming M-ary quadrature amplitude modulation (M-QAM) schemes and are evaluated numerically. Mont eCarlo simulation results of the LTE system are also providedto verify the accuracy of the mathematical analysis. It is shown that the results obtained from Monte-Carlo simulations match cl osely with those obtained from the derived mathematical formulas. KeywordsPerformance Analysis, MIMO, LTE, M-QAM Modulation. I. I NTRODUCTION To increase the capacity and speed of wireless communication systems, a new wireless data networks has been emerged and has been standardized by the 3rd Generation Partnership Project ( 3GPP). This new standard is a natural evolution to the existing second ( 2G) and third (3G) generation wireless networks in order to respond to the growing demand in terms of data rates and speed and marketed as 4G Long Term Evolution (LTE). In LTE, data throughput and the speed of wireless data are increased by using a combination of new methods and technologies like Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input MultipleOutput (MIMO) techniques. In the downlink, the LTE transmission is based on Orthogonal Frequency Division Multiple Access (OFDMA), known as a technique of encoding digital data on multiple carrier frequencies. It was shown that OFDMA is an efficient technique to improve the spectral efficiency of wireless systems . By converting the wide-band frequency selective channel in to a set of several flat fading subchannels, OFDM technique becomes more resistant to frequency selective fading than sin gle carrier systems. As OFDM signals are in time and frequency domain, they allow adding frequency domain scheduling to time domain scheduling. In LTE, for a given transmission power, the system data throughput and the coverage area can be optimized by employing Adaptive Modulation and Coding (AMC) techniques. The role of the user scheduler at the transmitter side is to assign the data rate for each user according to the channel conditions from the serving cell, t he interference level from other cells, and the noise level at t he receiver side. In LTE standard, the use of MIMO has been considered as an essential technique in order to achieve the target in terms of data throughput and reliability. MIMO is known to be a very powerful technique to improve the system performance of wireless communication systems. The divers ity and multiplexing modes are the two main modes of operation of multiple antennas systems. The principle of diversity mo de is based on transmitting the same signal over multiple anten nas and hence to improve the reliability of the system by the diversity gain. In this mode, the mapping function of transm it symbols used at the transmit antennas is called Space Time Block Code (STBC). On the other hand, multiplexing mode uses two or more different spatial streams and send them through two different antennas, consequently, the data rat e c n be improved. To study the performance of LTE systems a MATLAB based downlink physical layer simulator for Link Level Simulatio n (LLS) has been developed in [1] [2]. A System Level Simulation of the Simulator is also available [3]. The goal of developing the LTE simulator was to facilitate comparison with the work of different research groups and it is publicly available for free under academic non-commercial use licen se [2]. The main features of the simulator are adaptive coding and modulation, MIMO transmission and scheduling. As the simulator includes many physical layer features, it can be used for different applications in research [3]. In [4], the simulator was used to study the channel estimation of OFDM systems and the performance evaluation of a fast fading channel estimator was presented. In [5] and [6], a method for calculating the Precoding Matrix Indicator (PMI), the Rank Indicator (RI), and the Channel Quality Indicator (CQI) wer e studied and analyzed with the simulator. In this paper, the Bit Error Rate (BER) analysis of two transmit diversity schemes known as Space Frequency Block Codes (SFBC) and Frequency Switched Transmit Diversity (FSTD) MIMO schemes in LTE system for M-QAM modulation scheme are presented in terms of SNR using the moment g nerating function of the SNR. The results obtained from 190 Copyright (c) IARIA, 2013. ISBN: 978-1-61208-284-4 ICWMC 2013 : The Ninth International Conference on Wireless and Mobile Communications

A deterministic analysis of spatial diversity is presented in connection with radar systems. A numerical technique based on physical optics is used for our analysis. Contrary to statistical models, the proposed technique takes into account accurate near-field radar cross section of the target, and radiation characteristics of transmitting and receiving antennas. The power scattered by the target and received by multiple antennas as a function of the target aspect angle and distance is analyzed. Two combining methods of received powers are tested and statistical analysis is performed showing that, using spatial diversity, the angular range can be increased significantly and the standard deviation of the target response can be reduced. In order to validate our analysis and proposed scheme, experimental measurements were carried out using a metallic plate and a car as targets. This work has potential applications in automotive collision warning/avoidance radar systems.

In this paper, we present a comprehensive performance analysis of the 2x2 wireless MIMO Alamouti coding scheme using receive antenna selection. Complete knowledge at the receiver of the Channel State Information (CSI), i.e., perfect knowledge of both the symbol synchronisation and the channel gains, and a MIMO model of uncorrelated Rayleigh fading subchannels are assumed. A receive selection algorithm based on the maximizing Signal to Noise Ratio (SNR) is used to select two antennas. Under these conditions, we derive the exact average Bit Error Rate (BER) for Binary Phase Shift Keying (BPSK) modulation using the Moment Generating Function (MGF) and the order statistics associated with the instantaneous SNR at the two selected antennas.

In this paper, we consider a dense ad hoc network with multicast type of traffic handling using a hierarchical routing with clustering. We investigate the scaling of throughput capacity versus the number of nodes and destinations. We construct an elementary spatial-temporal routing scheme that achieves the throughput capacity of a dense ad hoc wireless network with high probability as the number of nodes increases. The derived lower bound on the throughput capacity under the proposed routing strategy holds with probability one as the number of nodes goes to infinity. Finally, we provide numerical validation of the achievable throughput using a multicast capacity simulator based on the proposed constructive scheme.

This paper considers a general approach for the computation of all functional characteristics of a probabilistic wireless channel model using a bidirectional parametric description. It is shown that under mild conditions the WSSUS property is valid for these models and explicit relations are derived for the computation of the time-frequency autocorrelation from which one can easily derive the Doppler and delay power spectra. As an illustrative example, we consider the single ring of scatterers channel model. We also briefly mention how all these concepts can be generalized to the MIMO case.

The traditional mobile location systems are mainly based on trilateration/multilateration techniques. In wireless MIMO communication systems which utilize antenna array at both transmit and receive sides, the redundancy of multipath signals can be exploited to extract more parameters such as angle-of-arrival, angle-of-departure and delay-of-arrival using advanced array signal processing techniques. In this paper, based on estimated multipath signal parameters in wireless MIMO communication systems, we propose a novel machine learning approach to determine the position of mobile targets using only one base station. This approach adopted the nearest neighbor regressor as the learning machine to estimation the highly nonlinear relationship between the multipath signal parameters and the position of mobile target. The simulation results have demonstrated the viability of the proposed methodology. This solution breaks the bottleneck of conventional mobile positioning systems which have to require multilateration of at least three base stations.

The focus of this paper is on presenting new results on throughput capacity of wireless ad hoc networks with multicast traffic. In seminal works, Gupta and Kumar introduced a new line of research. It is about the asymptotic throughput capacity of dense wireless ad hoc networks as a function of the number of nodes in the network. In this paper, we present an upper bound on the throughput capacity of an ad hoc network with multicast traffic using a hierarchical routing strategy. We start first by generating the upper bound and the strategy gain for the 2-level hierarchical strategy. Then, we generalize the result for multi-level hierarchical routing by giving the recurrence expression of the multicast gain. Finally, we apply the basic result to a broadcast traffic in the network

A promising approach to improve the performance of mobile location system is the use of antenna arrays in both transmitter and receiver sides. Using advanced array signal processing techniques, such multiple-input multiple-output (MIMO) communication systems can offer more mobile location information by exploiting the spatial properties of the multipath channel. In this pa- per, we propose a novel approach to determine the position of mo- bile terminal based on estimated multipath signal parameters using only one base station in MIMO communication systems. This approach intends to minimize the error occurring from the estimation of multiple paths and gives an optimal estimation of the position of mobile terminal by simultaneously calculating a set of nonlinear location equations. This solution breaks the bottleneck of conventional mobile location systems which have to require multi-lateration of at least three base stations.

We propose a novel approach in the context of multiple-input multiple-output communication systems to determine the position of mobile terminals based on estimated multipath signal parameters such as angle-of-arrival, angle-of-departure and delay-of-arrival using only one base station. This approach minimizes the errors occurring from the estimation of multipath parameters and gives the position of the mobile terminal by simultaneously resolving a set of algebraic location equations. The root-mean-square (RMS) errors are measured and compared with the Cramer-Rao lower bound to demonstrate the performance of the proposed method.

Wireless location is the procedure that determines the position of the mobile station in a wireless network. The traditional mobile location systems such as direction finding and ranging are based on trilateration/multilateration techniques. In wireless MIMO communication systems which utilize antenna array at both transmit and receive sides, the redundancy of multipath signals can be exploited to extract more parameters such as angle-of-arrival, angle-of-departure and delay-of-arrival using advanced array signal processing techniques. In this paper, based on estimated multipath signal parameters in the context of MIMO communication systems, we propose a novel approach to determine the position of mobile stations using only one base station. This approach minimizes the errors occurring from the estimation of multipath parameters and gives an optimal estimation of the position of the mobile station by simultaneously resolving a set of algebraic location equations. The mean-square errors are measured and compared with the Cramer-Rao lower bound to demonstrate the performance of the proposed method. This solution breaks the bottleneck of conventional mobile positioning systems which have to require multi-lateration of at least three BSs.

The focus of this paper is on presenting new results on throughput capacity of wireless ad hoc networks with multicast traffic. In seminal works [1], Gupta and Kumar introduced a new line of research. It is about the asymptotic throughput capacity of dense wireless ad hoc networks as a function of the number of nodes in the network. First, we present results on asymptotic behavior of a random ad hoc network based on simulations and analytical methods. Then, we present an upper bound on the throughput capacity of an ad hoc network with multicast traffic using a hierarchical routing strategy. We start by generating the upper bound and the strategy gain for the 2-level hierarchical strategy. Then, we generalize the result for multilevel hierarchical routing by giving the recurrence expression of the multicast gain. Finally, we apply the basic result to a broadcast traffic in the network. I. I NTRODUCTION Wireless ad hoc networks consist of a collection of nodes which communicate between them through a wireless channel and cooperate to route the information from a source node to its destination. Formally, a Mobile Ad hoc NETwork (MANET) is a system of wireless mobile nodes that dynamically self-organize in arbitrary and temporary networ k topologies. The principle characteristics of a wireless ad hoc network are its dynamic topology, limited bandwidth, energ etic constraints, security problems and absence of infrastruct u e. There has been recent interest in designing and analyzing ad-hoc wireless networks since they could be an alternate wireless network architecture to the traditional hierarch ical cellular architecture. The routing problem was the most stu died until recently and many algorithms have been developed [2], [3]. In other words, in ad hoc wireless networks the nodes act both as sources of information as well as relays for traffic handling on behalf of other nodes through multihopping. Con sequently, the simultaneous transmissions in ad hoc networ ks limit its per-user rate. So it is imperative to understand th e fundamental capacity performance limits, in terms of throu ghput and delay, of ad hoc wireless networks, with the goal of designing resource allocation (power control, medium acce ss, routing...) algorithms that allow to reach these performan ce limits. A new line of research has been initiated which is the asymptotic throughput of dense wireless networks. It ha s been established as a function of the number of nodes in the network. In seminal works [1], Gupta and Kumar showed that the per-user rate asymptotically decreases to zero when the number of nodes goes to infinity. It is then possible to achiev e a per node capacity of Θ( 1 √ n log n )1, using global scheduling and near straight route lines. The log n factor is present because each node radio transmission range needs to increas e as log n in order for an ad hoc network to stay connected with high probability as the number of nodes increases. In [4], Grossglauser and Tse have shown that if the nodes of the networks are moving quickly and independently, then a constant rate per communication pair can be achieved by a single relay strategy. However, this strategy can induce large delays, particularly in the situation where nodes are less mobile. In [5], El gamal and al. analyze the capacity/delay tradeoff by designing new communication strategies. In [6] , the authors discuss the limitations of the work in [1], by taking a network information theoretic approach. The autho rs iscuss how several co-operative strategies such as interf erence cancellation, network coding etc. could be used to improve t he throughput. However these tools cannot be exploited fully w ith the current technology, which relies on point-to-point cod ing, and treats all forms of interference as noise. In this paper, we develop performance bounds on the throughput capacity of an ad hoc network with multicast traffic. II. SYSTEM MODEL A. Network Model Let n nodes be uniformly and independently distributed in a planar square of unit area. Two nodes can directly communicate with each other if the distance between them is no more thanr(n), where r(n) is the signal range of these nodes. The ad hoc network consists then of n nodes Xi, i ∈ [1..n], each node can be either a source, a destination or a relay node. Furthermore, we assume that each source node has an infinite reservoir of packets 2 to send to its destination. We will denote bydij the distance between nodes i and j. Finally, 1f(n) = Θ(g(n)) if and only if |f(n)| ≤ c|g(n)| and |g(n)| ≤ c|f(n)| for constantc andc and for a large enough n 2This implies that we neglect buffering problems each node can transmit at W bits per second over a common wireless channel. B. Interference Model We consider an ad hoc network with n nodes which share a common wireless channel and can act as transmitters and receivers. Assume time is divided into equal slots. In each time slot, a node is scheduled to send data. A node cannot transmit and receive data simultaneously and a node can only receive data from another node at the same time. For the interference model, we adopt the ”the protocol model” presented in [1]. Suppose node Xi transmits to a node Xj . Then this transmission is successfully received by node Xj if and only if: • The distance between Xi andXj is no more thanr(n), i.e., |Xi − Xj | ≤ r(n) • For every other node simultaneously transmitting over the same channel |Xk − Xj | ≥ (1 + ∆)r(n) The quantity∆ > 0 models situations where a guard zone is specified by the protocol to prevent a neighboring node from transmitting on the same channel at the same time. It also allows for imprecision in the achieved range of transmissio n . III. T ECHNICAL LEMMAS In this section, we present results on the asymptotic behavi or of random ad hoc netwoks. Based on simulations of the network topology and the traffic model we show numerically the validity of some technical lemmas [1], [4], [5]. A. Cell partitioning As illustrated in figure 1, we assume the area of the network to be partitioned in a set of k regular cells. Each cell is a square of areaa = 1/k. The number of cells will in general depend on n, hence we will usek(n) to represent this parameter.

This paper proposes to model each cell of future wireless networks as a G/G/c/c queueing system. As such a model has not been explicitly addressed in the literature, we apply maximum entropy principles to evaluate both traffic distribution and blocking probability within each cell. Analysis of numerical results enables to specify the conditions under which the system offers good quality of service in terms of blocking probability. More specifically, such an analysis reveals that coefficient of variation of call arrivals has more impact over the blocking probability than coefficient of variation of channel holding time.

The rapid growth in demand for location based service has encouraged research into the performance improvement for wireless sensor positioning systems. Most of proposed localization techniques for wireless sensor networks rely on multilateration or cooperative localization. In this paper, we propose a novel approach in the context of multiple-input multiple-output (MIMO) communication technique to determine the position of sensor nodes. MIMO communication systems use antenna array in both source and receive nodes to exploit the spatial properties of the multipath channel, thereby offering more information for sensor positioning. Based on estimated multipath signal parameters such as angle-of-arrival, angle-of-departure and delay-of-arrival through adaptive array signal processing techniques, the proposed approach try to minimize the errors occurring from the estimation of multipath signal parameters and gives an optimal estimation of the position of the neighbor sensor node by simultaneously resolving a set of nonlinear location equations. Computer simulations show that the position of sensor node can be determined using only one other sensor node. The mean-square errors are measured and compared with the Cramer-Rao Lower Bound to demonstrate the performance of the proposed method.

In the Next-Generation (NG) wireless systems, mobile users (MUs) will be able to move across various heterogeneous networks while using their mobile terminals (MTs) to communicate. It has been proven that this global roaming freedom significantly increases the network-signaling traffic. Several schemes have been recently proposed to reduce such a traffic. This paper presents an efficient approach which uses a special gateway called Wireless INterworking Gateway (WING) to facilitate interoperability between heterogeneous subsystems of the NG wireless systems. Results reveal that such an approach significantly improves the network performance, in terms of generated signaling traffic and response time during the global roaming process.

The Next-Generation (NG) wireless systems are intended to unify many current systems into a seamless infrastructure, capable of offering a wide range of services to both mobile and fixed users. Planning such systems remains a challenging process which requires coping simultaneously with a large number of different aspects, such as the system performance, the network capacity, the radio coverage analysis, the signaling traffic, as well as the mobility management and the access technology. This paper presents a methodology which identifies the main planning factors and specifies the interactions between them in order to optimize both infrastructure costs and the capacity of the NG wireless systems. The main contribution resides in the identification of the parameters exchanged between each pair of modules which implement the identified factors.

Several strategies have been proposed recently to improve the performance of the IS-41 location management scheme. A forwarding pointers' strategy and a built-in memory strategy are proposed to reduce the signaling cost for location update and improve the IS-41 location update procedure. In this paper, we present a performance analysis of each strategy in an arbitrary time interval. In this analysis, users are classified by their call to mobility ratio which is defined as the call arrival rate divided by the mobility rate. We evaluate each of these strategies using this call to mobility ratio in order to come up with a set of recommendations that determine when each strategy is beneficial and for which class of users. We provide also a simplified analysis of the database loads generated by each strategy.

The next-generation (NG) wireless systems are envisioned to integrate the current communication systems into a seamless infrastructure, capable of allowing mobile users (MU) to access a wide range of high bandwidth wireless services. This integration of heterogeneous networks makes it difficult to locate MU as these MU move across networks using different access technologies and protocols. In this context, global roaming management constitutes a challenging problem. This paper presents an efficient approach which facilitates interoperability between heterogeneous networks during global roaming situations. Preliminary results reveal that such an approach significantly improves the performance of the NG wireless systems in terms of generated signaling traffic and response time during the global roaming process.