J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Englewood Cliffs, NJ: Prentice-Hall, 1999, pp. 285--305.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....five users per cell [1] and will decrease with increasing number of users. The limitations have in turn inspired a considerable body of research toward improving performance of wireless data networks. Achievements of such research include smarter radio transmission (e.g. adaptive array antennas) [17], better channel access schemes [30] more efficient scheduling schemes [19] faster and intelligent hand offs [25] and transport protocols that are wireless aware [4, 26] Although the aforementioned approaches do improve the performance of wireless data networks, they are inherently limited by ....

J. C. Liberti and T. S. Rappaport. Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Prentice Hall, Upper Saddle River, NJ USA, 1999.

....thus improve link quality. The study in [33] concentrates on designing a MAC protocol which can support the SEND primitive supporting the use of directional antenna. While these studies refer to traditional wireless networks rather than ad hoc networks, the use of multiple antennas for beamforming [36] can make directional transmission practical for mobile ad hoc nodes as well as for more traditional wireless nodes. Another concern in using directional wireless communication in ad hoc networks is that the position of the nodes is typically not known a priori and therefore the directional ....

J. Liberti and T. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Prentice Hall, 1st ed., 1999.

....with different quality of service classes [1] The expected growth demand for system capacity, especially in urban areas, will require the use of advanced techniques to increase the spectrum efficiency achievable with today s technology. One possible solution is the use of antenna arrays [2] [4]. This has already been considered by 3GPP (3rd Generation Partnership Project) as a possible performance enhancing feature for Universal Terrestrial Radio Access (UTRA) in both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes. In TDD mode the same carrier frequency is used ....

J. C. Liberti, T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, 1999.

.... application needs to be tested together with a propagation channel model characterising both Time of Arrival (ToA) and Angle of Arrival (AoA) e.g. 1] 5] In this work, a micro cell Wideband Directional Channel Model (WDCM) based on the Geometrically Based Single Bounce (GBSB) models [6], is used. It includes clusters of scatterers, and it is adjusted to a street type scenario [7] having been assessed by field measurements [8] Thus, a beamforming solution is applied to WDCM scenario concretisations, rich in many correlated, or closely correlated, signals arriving at the array ....

....L. Furthermore, the number of array elements, M, has been varied for #Lu d MT scenarios, whereas M = 12 for the latter cases. Table 2 presents the average ToA spread, Dt, and narrowband (NB) and wideband (WB) AoA spreads, Df NB and Df WB , respectively. These have been calculated according to [6], 8] for each DCIR, then calculating their mean over 100 independent DCIRs. The whole angular spread, Df NB , not taking the temp oral dimension into account, corresponds to 180 sectorisation. Df WB is calculated as a function of ToA: Df WB, 0 solely for the DCIR non delayed contributions, and ....

Liberti,J.C. and Rappaport,T.S., Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, Upper Saddle River, NJ, USA, 1999.

....the direction of the interfering users signals. Popular beamforming algorithms like the Recursive Least Squares (RLS) algorithm use a training sequence to obtain the desired beam pattern, while blind beamforming methods such as the Constant Modulus Algorithm (CMA) do not impose such a requirement [10]. Smart antennas are implemented as an array of omnidirectional antenna elements, each of which is fed with the signal, with an appropriate change in it s gain and phase. This array of complex quantities, constitutes a steering vector, and allows the resultant beam to form the main lobe and nulls ....

J. C. Liberti and T. S. Rappaport. Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Prentice Hall, Upper Saddle River, NJ, 1999.

....composed by a transmitter, a transmission channel and a receiver. A. Transmitters The transmitters are compliant with the 3GPP specifications for UMTS TDD. B. Channel Model The channel model used in this work was the Geometrical Based Single Bounce Elliptical Model (GBSBEM) proposed by Liberti [6]. This model was developed for microcell and picocell environments. The propagation channel is characterized by L paths for each user, one in line of sight plus L 1 arriving from remote reflectors located randomly within an ellipsis where the base station and the mobile unit are at the foci. ....

J. C. Liberti, T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, 1999.

....the function of optimizing the radiation pattern according to the environment. To cope with interference, smart antennas or adaptive array processing may be utilized to shape the antenna radiation pattern in such a way to enhance the desired signals and null the e#ect of the interfering signals [2]. By increasing the complexity of this array signal processing , it is possible to achieve greater performance improvements than are attainable using switched beam systems. This adaptive processing is generally known as optimum combining and It is based on the assumption that we already know a ....

....Fig. 2. The hexagonal Array. 0 7803 7589 0 02 17.00 2002 IEEE PIMRC 2002 An important parameter in the array design is the spacing between the elements. Grating lobes appear in the antenna radiation pattern if the spacing between the elements is greater that # 2, where # is signal wavelength [2]. Another e#ect that limits the spacing between the elements is the mutual coupling, because the closer the elements are the bigger the coupling influence will be. To shape and update the radiation pattern, besides feeding di#erent elements of the array, It is necessary to change the phase ....

Joseph C. Liberti and Theodore S. Rappaport Jr., Smart Antennas for Wireless Communications IS-95 and Third Generation CDMA Applications, Prentice Hall PTR, 1999.

....Adaptive beamforming using antenna arrays is widely used to reduce interference and mitigate multipath fading, hence improve capacity. Adaptive arrays cancel multipath components of the desired signal and remove interfering signals that have different directions of arrival from the desired signal [6] [8] Beamforming in conjunction with space time block coding is briefly considered in ref. 9] where the authors show that orthogonal transmit diversity can also be applied to beams. An extension of the space time transmit diversity approach, to the case of beamforming using two distinct beams, ....

J.C. Liberti and T.S. Rappaport, Smart Antenna for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, 1999.

....very low transmission rates. Moreover the system utilization was extremely ine# cient (only one voice call in over 200 kHz) Rising demands for better services led to deployment of second generation standards. 1.2. 2 Second generation wireless system The second generation wireless systems [5, 6, 7] are characterized by digital airinterface technology. They also started to o#er data services along with voice and is presently the most widely deployed system. Table 1.1 provides a comparative study of the various 2G based systems currently in operation. The second generation 4 Network ....

J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Prentice Hall Publishing, 1999. Upper Saddle River, NJ.

....and one particular channel concretisation. One can see that there is convergence after the 7 th iteration. As expected, these norms differ greatly also for case #5, relative to those of the other cases (not shown) C. SINR and BER Results The calculation of the SINR for CDMA follows (12) [11]: 1 1 T DesS J NDesI j p P SINR PN G = 12) where G p is the processing gain, P DesS and P NDesI are the DesS and NDesI powers, respectively, and N is the total noise power. In Figs. 2 and 3, average SINR and BER (e.g. 12] levels are shown, respectively, function of the ....

Liberti,J.C. and Rappaport,T.S., Smart Antennas for wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, Upper Saddle River, NJ, USA, 1999.

....more advanced approaches will be fuelled by capacity requirements and the need to offer customers more attractive features. Through range extension, advanced spatial processing (SP) techniques can reduce the number of BS that initially has to be deployed to provide coverage to critical areas [5]. However since the target of the MUD (multi user detection) techniques is only to mitigate the Multiple Access Interference (MAI) they only make sense when the number of customers is high enough. The cost benefit ratio of advanced techniques over the conventional ones must be taken into account. ....

....(LoS 1 remote reflector) The AoA, the path delay and the tap phase of the remote reflector depend on the remote reflectors positions. To simulate those parameters for a micro channel environment, the Geometrically Based Single Bounce Elliptical channel Model (GBSBEM) proposed by Liberti in [5] was used. To simulate the same channel conditions in the advanced and reference LLEPs, the same GBSBEM was used with the exception that the AoA is not needed for the reference link. For the advanced link, an UCA with 8 isotropic elements spaced l 2 was considered. The scenarios used to test the ....

J. C. Liberti, T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, 1999.

....correlation coefficient. In STAP systems, the situation is quite different from that of the conventional adaptive antenna. Due to multipath propagation [5] transmitting signals are spread in both time and space [6] therefore, the receiving signals are of the joint space time characteristics [7,8,14,15]. The space time characteristic is represented by the space time channel impulse response, or named as the space time channel waveform. As is shown in the signal model of [10] the space time channel waveform of a given user is the linear combination of the associated steering vector of multipath ....

J. C. Liberti,JR and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, Inc., 1999.

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J. C. Liberti and T. S. Rappaport, Smart antennas for wireless communica- tions: IS-95 and third generation CDMA applications. Upper Saddle River, N J: Prentice Hall, 1999.

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J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Englewood Cliffs, NJ: Prentice-Hall, 1999, pp. 285--305.

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J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, NJ, Prentice Hall, 1999.

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J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Englewood Cliffs, NJ: Prentice-Hall, 1999.

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J. C. Liberti Jr. and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Englewood Cliffs, NJ: Prentice-Hall, 1999.

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J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, NJ, Prentice Hall, 1999.

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J. C. Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall, 1999.

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J. C Liberti and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Englewood Cliffs, NJ: Prentice-Hall, 1999.

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J. C. Liberti, Jr. and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall PTR, Upper Saddle River, NJ 07458, 1999.

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J. C. Liberti Jr. and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice Hall PTR, NJ, 1999.

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J. C. Liberti, and T. S. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications, Prentice-Hall, 1999.

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J. Liberti and T. Rappaport, Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications. Prentice Hall, 1st ed., 1999.

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J. C. Liberti and T. Rappaport, Smart Antennas for Wireless Communications: IS 95 and Third Generation CDMA Applications, Prentice Hall, Upper Saddle River, NJ, 1 st edition, 1999.

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