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M Nasshan - One of the best experts on this subject based on the ideXlab platform.

  • results on turbo codes for speech transmission in a joint detection cdma Mobile Radio System with coherent receiver antenna diversity
    IEEE Transactions on Vehicular Technology, 1997
    Co-Authors: Peter Jung, M Nasshan
    Abstract:

    Turbo-codes which are applicable to speech transmission in digital Mobile Radio Systems are treated. Three turbo-codes of different complexity are presented. The proposed turbo-codes are suitable for the application to speech transmission in the joint detection code-division multiple access (JD-CDMA) Mobile Radio System with coherent receiver antenna diversity (CRAD) which are described concisely. The performance of the designed turbo-codes in terms of bit and frame error rates are shown in the case of additive white Gaussian noise (AWGN) channels, flat Rayleigh fading channels, and in the uplink of the aforementioned JD-CDMA Mobile Radio System.

  • performance of a cellular hybrid c tdma Mobile Radio System applying joint detection and coherent receiver antenna diversity
    IEEE Journal on Selected Areas in Communications, 1994
    Co-Authors: Josef Blanz, M Nasshan, Anja Klein, A Steil
    Abstract:

    For future Mobile Radio Systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In the paper, a hybrid C/TDMA System using joint detection (JD-C/TDMA) with coherent receiver antenna diversity (CRAD) at the base station (BS) receiver is proposed. Some attractive features of the JD-C/TDMA System are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high System capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover. The single cell E/sub b//N/sub 0/ performance and the interference situation in a cellular environment of the uplink of a JD-C/TDMA Mobile Radio System with CRAD is investigated in detail. It is shown that the cellular spectrum efficiency is remarkably high, taking values up to 0.2 bit/s/Hz/BS in the uplink, depending on the actual transmission conditions. >

  • dependence of the error performance of turbo codes on the interleaver structure in short frame transmission Systems
    Electronics Letters, 1994
    Co-Authors: Peter Jung, M Nasshan
    Abstract:

    The dependence of both bit and frame error performance, respectively, of the novel parallel concatenated recursive Systematic codes, termed turbo-codes, on the interleaver structure is investigated in frame transmission Systems with frames containing 192 bits required for speech transmission in a possible future Mobile Radio System.< >

  • performance evaluation of turbo codes for short frame transmission Systems
    Electronics Letters, 1994
    Co-Authors: Peter Jung, M Nasshan
    Abstract:

    The bit and frame error performance of a novel class of parallel concatenated recursive Systematic codes termed turbo codes is investigated in frame transmission Systems with frames containing 192 bits required for speech transmission in a possible future Mobile Radio System. Optimisation of the encoder by interleaver design is also considered.

  • performance of a cellular hybrid c tdma Mobile Radio System applying joint detection and coherent receiver antenna diversity
    MILCOM '93, 1994
    Co-Authors: Josef Blanz, M Nasshan, Anja Klein, A Steil
    Abstract:

    For future Mobile Radio Systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In this paper, a hybrid C/TDMA System using joint detection (JD-C/TDMA) with coherent receiver antenna diversity (CRAD) at the base station (BS) receiver is proposed. Some attractive features of the JD-C/TDMA System are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high System capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover

Peter Jung - One of the best experts on this subject based on the ideXlab platform.

  • Optimum and suboptimum channel estimation for the uplink of CDMA Mobile Radio Systems with joint detection
    European Transactions on Telecommunications, 2010
    Co-Authors: Bernd Steiner, Peter Jung
    Abstract:

    In the present paper, channel estimation in the uplink of CDMA Mobile Radio Systems with burst transmission applying joint detection is considered. The different Radio channels are estimated at the receiver using known midamble codes. Either maximum-likelihood, i.e. optimum, or suboptimum channel estimation can be realized at the receiver. Several methods for constructing code sets for the simultaneously active users are proposed. It is shown that the structure of the channel estimator for a multi-user synchronous CDMA Mobile Radio System is the same as for a single-user System when the mid amble codes of the users are segments derived from a single basic code. Furthermore, it is shown that the channel estimator can be implemented as a correlator when the midamble codes are constructed from a periodic basic code. Finally, the effect of noisy channel estimation, i.e. the presence of channel estimation errors, on the detected data is examined.

  • results on turbo codes for speech transmission in a joint detection cdma Mobile Radio System with coherent receiver antenna diversity
    IEEE Transactions on Vehicular Technology, 1997
    Co-Authors: Peter Jung, M Nasshan
    Abstract:

    Turbo-codes which are applicable to speech transmission in digital Mobile Radio Systems are treated. Three turbo-codes of different complexity are presented. The proposed turbo-codes are suitable for the application to speech transmission in the joint detection code-division multiple access (JD-CDMA) Mobile Radio System with coherent receiver antenna diversity (CRAD) which are described concisely. The performance of the designed turbo-codes in terms of bit and frame error rates are shown in the case of additive white Gaussian noise (AWGN) channels, flat Rayleigh fading channels, and in the uplink of the aforementioned JD-CDMA Mobile Radio System.

  • dependence of the error performance of turbo codes on the interleaver structure in short frame transmission Systems
    Electronics Letters, 1994
    Co-Authors: Peter Jung, M Nasshan
    Abstract:

    The dependence of both bit and frame error performance, respectively, of the novel parallel concatenated recursive Systematic codes, termed turbo-codes, on the interleaver structure is investigated in frame transmission Systems with frames containing 192 bits required for speech transmission in a possible future Mobile Radio System.< >

  • performance evaluation of turbo codes for short frame transmission Systems
    Electronics Letters, 1994
    Co-Authors: Peter Jung, M Nasshan
    Abstract:

    The bit and frame error performance of a novel class of parallel concatenated recursive Systematic codes termed turbo codes is investigated in frame transmission Systems with frames containing 192 bits required for speech transmission in a possible future Mobile Radio System. Optimisation of the encoder by interleaver design is also considered.

Ljiljana Trajkovic - One of the best experts on this subject based on the ideXlab platform.

  • analysis of public safety traffic on trunked land Mobile Radio Systems
    IEEE Journal on Selected Areas in Communications, 2004
    Co-Authors: D S Sharp, N Cackov, N Laskovic, Qing Shao, Ljiljana Trajkovic
    Abstract:

    Mobile Radio Systems for public safety and agencies engaged in emergency response and disaster recovery operations must support multicast voice traffic. In this paper, we analyze the distribution of call interarrival and call holding times for multicast voice (talk group) traffic on a transmission trunked Mobile Radio System. In such Systems, the channel is held only while a user is making a call (while the push-to-talk key is pressed and the Radio is transmitting). We find that the call interarrival time distributions are exponential and exhibit tendency toward long-range dependence. The call holding times best fit lognormal distributions and are not correlated. A potentially important implication of these findings is that performance estimation methods that assume memoryless Markov arrival and departure processes may not be viable approaches.

J H Winters - One of the best experts on this subject based on the ideXlab platform.

  • the impact of antenna diversity on the capacity of wireless communication Systems
    IEEE Transactions on Communications, 1994
    Co-Authors: J H Winters, J Salz, Richard D Gitlin
    Abstract:

    For a broad class of interference-dominated wireless Systems including Mobile, personal communications, and wireless PBX/LAN networks, the authors show that a significant increase in System capacity can be achieved by the use of spatial diversity (multiple antennas), and optimum combining. This is explained by the following observation: for independent flat-Rayleigh fading wireless Systems with N mutually interfering users, they demonstrate that with K+N antennas, N-1 interferers can be nulled out and K+1 path diversity improvement can be achieved by each of the N users. Monte Carlo evaluations show that these results also hold with frequency-selective fading when optimum equalization is used at the receiver. Thus an N-fold increase in user capacity can be achieved, allowing for modular growth and improved performance by increasing the number of antennas. The interferers can also be users in other cells, users in other Radio Systems, or even other types of radiating devices, and thus interference cancellation also allows Radio Systems to operate in high interference environments. As an example of the potential System gain, the authors show that with 2 or 3 antennas the capacity of the Mobile Radio System IS-54 can be doubled, and with 5 antennas a 7-fold capacity increase (frequency reuse in every cell) can be achieved. >

  • signal acquisition and tracking with adaptive arrays in the digital Mobile Radio System is 54 with flat fading
    IEEE Transactions on Vehicular Technology, 1993
    Co-Authors: J H Winters
    Abstract:

    The author considers the dynamic performance of adaptive arrays in wireless communication Systems. With an adaptive array, the signals received by multiple antennas are weighted and combined to suppress interference and combat desired signal fading. In these Systems, the weight adaptation algorithm must acquire and track the weights even with rapid fading. The author considers the performance of the least-mean-square (LMS) and direct matrix inversion (DMI) algorithms in the North American digital Mobile Radio System IS-54. He shows that implementation of these algorithms permits the use of coherent detection, which improves performance by 1 dB over differential detection. Results for two base station antennas with flat Rayleigh fading show that the LMS algorithm has large tracking loss for vehicle speeds above 20 mph, but the DMI algorithm can acquire and track the weights to combat desired signal fading at vehicle speeds up to 60 mph with less than 0.2 dB degradation from ideal performance with differential detection. Similarly, interference is also suppressed with performance gains over maximal ratio combining within 0.5 dB of the predicted ideal gain. >

  • signal acquisition and tracking with adaptive arrays in wireless Systems
    Vehicular Technology Conference, 1993
    Co-Authors: J H Winters
    Abstract:

    The dynamic performance of adaptive arrays in wireless communication Systems is considered. With an adaptive array, the signals received by multiple antennas are weighted and combined to suppress interference and combat desired-signal fading. In these Systems, the weight adaptation algorithm must acquire and track the weights even with rapid fading. The performance of the least-mean-square (LMS) and direct matrix inversion (DMI) algorithms in the digital Mobile Radio System IS-54 is considered. Results for two base station antennas with flat Rayleigh fading show that the LMS algorithm has large tracking loss for vehicle speeds above 20 mph, and that the DMI algorithm can acquire and track the weights to combat desired-signal fading and suppress interference with close to ideal tracking performance at vehicle speeds up to 60 mph.

D S Sharp - One of the best experts on this subject based on the ideXlab platform.

  • analysis of public safety traffic on trunked land Mobile Radio Systems
    IEEE Journal on Selected Areas in Communications, 2004
    Co-Authors: D S Sharp, N Cackov, N Laskovic, Qing Shao, Ljiljana Trajkovic
    Abstract:

    Mobile Radio Systems for public safety and agencies engaged in emergency response and disaster recovery operations must support multicast voice traffic. In this paper, we analyze the distribution of call interarrival and call holding times for multicast voice (talk group) traffic on a transmission trunked Mobile Radio System. In such Systems, the channel is held only while a user is making a call (while the push-to-talk key is pressed and the Radio is transmitting). We find that the call interarrival time distributions are exponential and exhibit tendency toward long-range dependence. The call holding times best fit lognormal distributions and are not correlated. A potentially important implication of these findings is that performance estimation methods that assume memoryless Markov arrival and departure processes may not be viable approaches.

  • Analysis of Public Safety Traffic on Trunked Land Mobile Radio Systems
    2004
    Co-Authors: D S Sharp, N Cackov, Qing Shao, Nenad Lasković, Ljiljana Trajković, Senior Member
    Abstract:

    Abstract—Mobile Radio Systems for public safety and agencies engaged in emergency response and disaster recovery operations must support multicast voice traffic. In this paper, we analyze the distribution of call interarrival and call holding times for multicast voice (talk group) traffic on a transmission trunked Mobile Radio System. In such Systems, the channel is held only while a user is making a call (while the push-to-talk key is pressed and the Radio is transmitting). We find that the call interarrival time distributions are exponential and exhibit tendency toward long-range dependence. The call holding times best fit lognormal distributions and are not correlated. A potentially important implication of these findings is that performance estimation methods that assume memoryless Markov arrival and departure processes may not be viable approaches. Index Terms—Analysis of voice traffic, Mobile communications, public safety networks, Radio Systems. I