Change search
Refine search result
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Chu, Thi My Chinh
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Phan, Hoc
    Univ Reading, GBR.
    Hybrid spectrum access with relay assisting both primary and secondary networks under imperfect spectrum sensing2016In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, article id 244Article in journal (Refereed)
    Abstract [en]

    This paper proposes a novel hybrid interweave-underlay spectrum access for a cognitive amplify-and-forward relay network where the relay forwards the signals of both the primary and secondary networks. In particular, the secondary network (SN) opportunistically operates in interweave spectrum access mode when the primary network (PN) is sensed to be inactive and switches to underlay spectrum access mode if the SN detects that the PN is active. A continuous-time Markov chain approach is utilized to model the state transitions of the system. This enables us to obtain the probability of each state in the Markov chain. Based on these probabilities and taking into account the impact of imperfect spectrum sensing of the SN, the probability of each operation mode of the hybrid scheme is obtained. To assess the performance of the PN and SN, we derive analytical expressions for the outage probability, outage capacity, and symbol error rate over Nakagami-m fading channels. Furthermore, we present comparisons between the performance of underlay cognitive cooperative radio networks (CCRNs) and the performance of the considered hybrid interweave-underlay CCRN in order to reveal the advantages of the proposed hybrid spectrum access scheme. Eventually, with the assistance of the secondary relay, performance improvements for the PN are illustrated by means of selected numerical results.

  • 2. Duong, Quang Trung
    et al.
    Zepernick, Hans-Jürgen
    On the Performance Gain of Hybrid Decode-Amplify-Forward Cooperative Communications2009In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2009Article in journal (Refereed)
    Abstract [en]

    In this paper, we investigate the performance of adaptive decode-forward (ADF), amplify-forward (AF), and hybrid decode-amplify-forward (HDAF) relaying protocol. In particular, we derive the closedform expression of symbol error probability (SEP) for these three relaying protocols. For the AF protocol, we derive a simpler and more tractable final result than previously published work [1]. Furthermore, analyzing the high signal-to-noise ratio (SNR) regime, we derive an asymptotically tight approximation for SEP. Especially, for the AF protocol, our SEP approximation is tighter than the result in [2]. The SEP approximation is used to assess an important aspect between the three different relaying protocols, i.e., the SEP performance gain of HADF over the two conventional relaying schemes ADF and AF. It is shown that the performance gain of HDAF over ADF and AF significantly depends on the relative value of channel conditions between source-to-relay and relay-to- estination link (relay channels). Interestingly, it is shown that the HDAF protocol has no benefit compare to the two others if the relay is located close to the source. In contrast, the performance gains of HDAF over the ADF and AF scheme are remarkably large as the relay moves nearby the destination. Specifically, the numerical results given as well as our analysis indicate that for QPSK modulation, HDAF outperforms ADF and AF with a performance improvement by 5 dB and 6 dB, respectively.

  • 3. Hult, Tommy
    WCDMA Uplink Interference Assessment from Multiple High Altitude Platform Configurations2008In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. vol. 2008, no Special Issue on Advanced Communication Techniques and Applications for High-Altitude PlatformsArticle in journal (Refereed)
    Abstract [en]

    We investigate the possibility of multiple high altitude platform (HAP) coverage of a common cell area using a wideband code division multiple access (WCDMA) system. In particular, we study the uplink system performance of the system. The results show that depending on the traffic demand and the type of service used, there is a possibility of deploying 3-6 HAPs covering the same cell area. The results also show the effect of cell radius on performance and the position of the multiple HAP base stations which give the worst performance.

  • 4. Mohammed, Abbas
    et al.
    Arnon, Shelomi
    Grace, David
    Mondin, Marina
    Miura, R
    Advanced Communication Techniques and Applications for High-Altitude Platforms2008In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499Article in journal (Refereed)
  • 5.
    Phan, Hoc
    et al.
    Blekinge Institute of Technology, School of Computing.
    Duong, Quang Trung
    Blekinge Institute of Technology, School of Computing.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, School of Computing.
    Shu, Lei
    Adaptive transmission in MIMO AF relay networks with orthogonal space-time block codes over Nakagami-m fading2012In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, no 11Article in journal (Refereed)
    Abstract [en]

    In this article, we apply different adaptive transmission techniques to dual-hop multiple-input multiple-output amplify-and-forward relay networks using orthogonal space-time block coding over independent Nakagami-m fading channels. The adaptive techniques investigated are optimal simultaneous power and rate (OSPR), optimal rate with constant power (ORCP), and truncated channel inversion with fixed rate (TCIFR). The expressions for the channel capacity of OSPR, ORCP, and TCIFR, and the outage probability of OSPR, and TCIFR are derived based on the characteristic function of the reciprocal of the instantaneous signal-to-noise ratio (SNR) at the destination. For sufficiently high SNR, the channel capacity of ORCP asymptotically converges to OSPR while OSPR and ORCP achieve higher channel capacity compared to TCIFR. Although TCIFR suffers from an increase in the outage probability relative to OSPR, it provides the lowest implementation complexity among the considered schemes. Along with analytical results, we further adopt Monte Carlo simulations to validate the theoretical analysis.

    Download full text (pdf)
    fulltext
  • 6.
    Tran, Hung
    et al.
    Blekinge Institute of Technology, School of Computing.
    Duong, Quang Trung
    Blekinge Institute of Technology, School of Computing.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, School of Computing.
    Delay performance of cognitive radio networks for point-to-point and point-to-multipoint communications2012In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, no 9Article in journal (Refereed)
    Abstract [en]

    In this article, we analyze the packet transmission time in spectrum sharing systems where a secondary user (SU) simultaneously accesses the spectrum licensed to primary users (PUs). In particular, under the assumption of an independent identical distributed Rayleigh block fading channel, we investigate the effect of the peak interference power constraint imposed by multiple PUs on the packet transmission time of the SU. Utilizing the concept of timeout, exact closed-form expressions of outage probability and average packet transmission time of the SU are derived. In addition, employing the characteristics of the M/G/1 queuing model, the impact of the number of PUs and their peak interference power constraint on the stable transmission condition and the average waiting time of packets at the SU are examined. Moreover, we then extend the analysis for point-to-point to point-to-multipoint communications allowing for multiple SUs and derive the related closed-form expressions for outage probability and successful transmission probability for the best channel condition. Numerical results are provided to corroborate our theoretical results and to illustrate applications of the derived closed-form expressions for performance evaluation of cognitive radio networks.

    Download full text (pdf)
    fulltext
  • 7. Yang, Zhe
    et al.
    Mohammed, Abbas
    Hult, Tommy
    Performance Evaluation of WiMAX Broadband from High Altitude Platform Cellular System and Terrestrial Coexistence Capability2008In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2008Article in journal (Refereed)
    Abstract [en]

    The performance obtained from providing worldwide interoperability for microwave access (WiMAX) from high altitude platforms (HAPs) with multiple antenna payloads is investigated, and the coexistence capability with multiple-operator terrestrial WiMAX deployments is examined. A scenario composed of a single HAP and coexisting multiple terrestrial WiMAX base stations deployed inside the HAP coverage area (with radius of 30 km) to provide services to fixed users with the antenna mounted on the roof with a directive antenna to receive signals from HAPs is proposed. A HAP cellular configuration with different possible reuse patterns is established. The coexistence performance is assessed in terms of HAP downlink and uplink performance, interfered by terrestrial WiMAX deployment. Simulation results show that it is effective to deliver WiMAX via HAPs and share the spectrum with terrestrial systems.

    Download full text (pdf)
    FULLTEXT01
  • 8. Yang, Zhe
    et al.
    Mohammed, Abbas
    Hult, Tommy
    Grace, David
    Downlink Coexistence Performance Assessment and Techniques for WiMAX Services from High Altitude Platform and Terrestrial Deployments2008In: EURASIP Journal on Wireless Communications and Networking, ISSN 1687-1472, E-ISSN 1687-1499, Vol. 2008Article in journal (Refereed)
    Abstract [en]

    We investigate the performance and coexistence techniques for worldwide interoperability for microwave access (WiMAX) delivered from high altitude platforms (HAPs) and terrestrial systems in shared 3.5 GHz frequency bands. The paper shows that it is possible to provide WiMAX services from individual HAP systems. The coexistence performance is evaluated by appropriate choice of parameters, which include the HAP deployment spacing radius, directive antenna beamwidths based on adopted antenna models for HAPs and receivers. Illustrations and comparisons of coexistence techniques, for example, varying the antenna pointing offset, transmitting and receiving antenna beamwidth, demonstrate efficient ways to enhance the HAP system performance while effectively coexisting with terrestrial WiMAX systems.

    Download full text (pdf)
    FULLTEXT01
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf