Opportunistic Routing gained lots of attention as a way to improve the performance of wireless multi-hop relay mesh networks. The key characteristic is its ability to take advantage of the numerous, yet unreliable wireless links in the network. The most important part of every opportunistic routing protocol is the forwarder selection algorithm. Most of the currently known protocols assume that signal paths from a sender to all candidates are independent to each other and therefore resulting in independent packet error rates. However, this assumption does not hold for spatially close candidates which are not so uncommon in indoor networks. In this paper, we present empirical measurements from our 802.11 indoor test-bed which reveal that signal paths to spatially close nodes are correlated. We believe that the loss in the radio propagation due to shadow fading is similar to spatially close nodes. For our setup we find out that a spatial correlation exists when the nodes are closer than 2 m to each other. We present a candidate set selection algorithm which is able to calculate the packet error rate of a candidate set even when the individual packet error rates are correlated, e.g. due to spatial correlation. Therefore only a simple modification to the existing ordinary link probing is required. Finally, we present modifications we made to our packet-level simulator to respect spatial correlation as well as simulation results.
{"title":"Considerations on forwarder selection for opportunistic protocols in wireless networks","authors":"A. Zubow, M. Kurth, J. Redlich","doi":"10.1109/EW.2008.4623904","DOIUrl":"https://doi.org/10.1109/EW.2008.4623904","url":null,"abstract":"Opportunistic Routing gained lots of attention as a way to improve the performance of wireless multi-hop relay mesh networks. The key characteristic is its ability to take advantage of the numerous, yet unreliable wireless links in the network. The most important part of every opportunistic routing protocol is the forwarder selection algorithm. Most of the currently known protocols assume that signal paths from a sender to all candidates are independent to each other and therefore resulting in independent packet error rates. However, this assumption does not hold for spatially close candidates which are not so uncommon in indoor networks. In this paper, we present empirical measurements from our 802.11 indoor test-bed which reveal that signal paths to spatially close nodes are correlated. We believe that the loss in the radio propagation due to shadow fading is similar to spatially close nodes. For our setup we find out that a spatial correlation exists when the nodes are closer than 2 m to each other. We present a candidate set selection algorithm which is able to calculate the packet error rate of a candidate set even when the individual packet error rates are correlated, e.g. due to spatial correlation. Therefore only a simple modification to the existing ordinary link probing is required. Finally, we present modifications we made to our packet-level simulator to respect spatial correlation as well as simulation results.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124657154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The use of statistical eigen-beamforming is effective in spatially correlated fading environments, but it may suffer from interference near the sector boundary when applied to the downlink with universal frequency reuse. This interference effect may not sufficiently be handled by a minimum mean square error (MMSE) receiver unless a sufficient number of receive antennas are employed. In this paper, we consider the use of multi-sector beamforming that cooperates with a neighboring sector in the same cell to mitigate this interference problem. By exploiting long-term channel state information (CSI), the proposed scheme can obtain transmit array gain without the use of instantaneous CSI, while avoiding interference from the adjacent cooperating sector. The performance of the proposed scheme is analyzed with combined use of an MMSE receiver and verified by computer simulation.
{"title":"Multi-sector beamforming with MMSE receiver in spatially correlated channel","authors":"Jae-Heung Yeom, Yong-Hwan Lee","doi":"10.1109/EW.2008.4623909","DOIUrl":"https://doi.org/10.1109/EW.2008.4623909","url":null,"abstract":"The use of statistical eigen-beamforming is effective in spatially correlated fading environments, but it may suffer from interference near the sector boundary when applied to the downlink with universal frequency reuse. This interference effect may not sufficiently be handled by a minimum mean square error (MMSE) receiver unless a sufficient number of receive antennas are employed. In this paper, we consider the use of multi-sector beamforming that cooperates with a neighboring sector in the same cell to mitigate this interference problem. By exploiting long-term channel state information (CSI), the proposed scheme can obtain transmit array gain without the use of instantaneous CSI, while avoiding interference from the adjacent cooperating sector. The performance of the proposed scheme is analyzed with combined use of an MMSE receiver and verified by computer simulation.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122903317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The emerging IEEE 802.11 family of wireless technologies has shown tremendous growth and acceptance as a last hop wireless solution in Local Area Networks (LANs). The use of multimedia networking applications has brought more requirements to the network, creating a need for end-to-end quality of service (QoS). In this context, the standard introduces one mechanism, called EDCA which provides a prioritized traffic to guarantee the QoS involving four different Access Category (ACs). The main problem of the original EDCA is that the values of the main parameters of each AC queue (such as contention window limits) are static and do not take into account wireless channel conditions. In this paper, we present a new approach to split the contention windows per AC into different sub-windows, ensuring that this partition decreases channel collisions while maintaining a low delay and high throughput. Our technique select on the fly, the sub-windows per AC taking into account both applications requirements and network conditions. Preliminary results on ad-hoc and infrastructure wireless networks show that the presented technique enhances the channel utilization, decreasing the delay and increasing the throughput.
{"title":"Adaptive tuning mechanism for EDCA in IEEE 802.11e wireless LANs","authors":"C. N. Ojeda-Guerra, Itziar G. Alonso-González","doi":"10.1109/EW.2008.4623862","DOIUrl":"https://doi.org/10.1109/EW.2008.4623862","url":null,"abstract":"The emerging IEEE 802.11 family of wireless technologies has shown tremendous growth and acceptance as a last hop wireless solution in Local Area Networks (LANs). The use of multimedia networking applications has brought more requirements to the network, creating a need for end-to-end quality of service (QoS). In this context, the standard introduces one mechanism, called EDCA which provides a prioritized traffic to guarantee the QoS involving four different Access Category (ACs). The main problem of the original EDCA is that the values of the main parameters of each AC queue (such as contention window limits) are static and do not take into account wireless channel conditions. In this paper, we present a new approach to split the contention windows per AC into different sub-windows, ensuring that this partition decreases channel collisions while maintaining a low delay and high throughput. Our technique select on the fly, the sub-windows per AC taking into account both applications requirements and network conditions. Preliminary results on ad-hoc and infrastructure wireless networks show that the presented technique enhances the channel utilization, decreasing the delay and increasing the throughput.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"846 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125055625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an analysis method of i.i.d. (independent and identically distributed) MIMO (multiple input multiple output) channels under Nakagami m fading environment based on statistical distributions of the largest eigenvalue which is useful for the analysis of MRC (maximal ratio combining) communication systems. Given distribution formulae are introduced utilizing the conversion of MIMO channels into equivalent SIMO models with the same number of diversity branches and total power equal to the per-branch largest eigenvalue mean. The derived density function has a simple monomial form which is suitable for calculations of various performance indices of MIMO systems. Through computer simulations, the effectiveness of the proposed approximated formulae is demonstrated. Impact of antenna number and Nakagami factor representing the depth of fading on the approximation precision is also investigated. In addition, exact eigenvalue distribution of MIMO Nakagami m pinhole channel is described from the theoretical viewpoint.
{"title":"Analysis method of MIMO MRC systems under nakagami m fading environment","authors":"T. Taniguchi, Makoto Tsuruta, Y. Karasawa","doi":"10.1109/EW.2008.4623907","DOIUrl":"https://doi.org/10.1109/EW.2008.4623907","url":null,"abstract":"This paper presents an analysis method of i.i.d. (independent and identically distributed) MIMO (multiple input multiple output) channels under Nakagami m fading environment based on statistical distributions of the largest eigenvalue which is useful for the analysis of MRC (maximal ratio combining) communication systems. Given distribution formulae are introduced utilizing the conversion of MIMO channels into equivalent SIMO models with the same number of diversity branches and total power equal to the per-branch largest eigenvalue mean. The derived density function has a simple monomial form which is suitable for calculations of various performance indices of MIMO systems. Through computer simulations, the effectiveness of the proposed approximated formulae is demonstrated. Impact of antenna number and Nakagami factor representing the depth of fading on the approximation precision is also investigated. In addition, exact eigenvalue distribution of MIMO Nakagami m pinhole channel is described from the theoretical viewpoint.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125328357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the wireless local area network (WLAN) standard IEEE 802.11b, complementary code keying (CCK) modulation has been adopted for the high data rate transmission mode. In this paper, complexity reduction for block decision-feedback equalization (bDFE), tailored for CCK transmission over frequency-selective channels, is considered. Since the CCK signal may be viewed as a linear block code with respect to the chip phases of the codeword, a trellis diagram with a minimum number of states can be designed that represents the properties of the CCK code set. The Viterbi algorithm (VA) with per-survivor processing is applied to the CCK trellis for decoding and accounting for the inter-chip interference, while inter-codeword interference is canceled by decision feedback. The resulting scheme is denoted as bDFE-pS and has a significantly lower complexity than bDFE with brute-force search. By introducing a sphere constraint on the CCK trellis (SC-bDFE-pS), the complexity of bDFE-pS can be further reduced. Omitting trellis states that violate the sphere constraint, edges that emanate from such states can be pruned, and the average number of metric calculations per CCK trellis segment can be reduced. Simulation results show that the performance of bDFE-pS and SC-bDFE-pS, respectively, is essentially equivalent to that of bDFE with brute-force search.
{"title":"Sphere constrained block DFE with per-survivor intra-block processing for CCK transmission over ISI channels","authors":"C. Jonietz, W. Gerstacker, R. Schober","doi":"10.1109/EW.2008.4623898","DOIUrl":"https://doi.org/10.1109/EW.2008.4623898","url":null,"abstract":"In the wireless local area network (WLAN) standard IEEE 802.11b, complementary code keying (CCK) modulation has been adopted for the high data rate transmission mode. In this paper, complexity reduction for block decision-feedback equalization (bDFE), tailored for CCK transmission over frequency-selective channels, is considered. Since the CCK signal may be viewed as a linear block code with respect to the chip phases of the codeword, a trellis diagram with a minimum number of states can be designed that represents the properties of the CCK code set. The Viterbi algorithm (VA) with per-survivor processing is applied to the CCK trellis for decoding and accounting for the inter-chip interference, while inter-codeword interference is canceled by decision feedback. The resulting scheme is denoted as bDFE-pS and has a significantly lower complexity than bDFE with brute-force search. By introducing a sphere constraint on the CCK trellis (SC-bDFE-pS), the complexity of bDFE-pS can be further reduced. Omitting trellis states that violate the sphere constraint, edges that emanate from such states can be pruned, and the average number of metric calculations per CCK trellis segment can be reduced. Simulation results show that the performance of bDFE-pS and SC-bDFE-pS, respectively, is essentially equivalent to that of bDFE with brute-force search.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121256869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Baccelli, B. Błaszczyszyn, Erwan Ermel, P. Mühlethaler
In this paper we present a new routing technique which can operate on mobile ad hoc networks. This technique is opportunistic in the sense that each packet on its (specific) route from an origin (O) to a destination (D) at each hop takes advantage from the current pattern of nodes who captured its recent (retransmission to choose the next relay. Note that this is unlike in conventional routing protocols, which first predetermine the relays on a route from O to D, e.g. with a shortest path algorithm, and then let a given medium access (MAC) protocol, e.g. Carrier-Sense Multiple Access (CSMA), deliver all the packets using this route. Moreover, in our technique, the current transmitter of a given packet does not know its next relay a priori, but the nodes who capture this transmission (if any) perform a self selection to chose the unique packet relay node and acknowledge the transmitter. Finally, the above relay self selection procedure is optimized in the sense that it is the node that optimizes some given utility criterion, e.g. minimizes the remaining distance to D, which is chosen as the relay. The primary goal of this paper is to explain how relay self selection can be achieved. Moreover, we show that this routing technique works well with various MAC protocols which may be controlled multiple access schemes or random access schemes. More precisely, assuming two different MAC protocols: Aloha and CSMA, we use simulations to compare the performance of this new routing technique to conventional shortest path routing. In this particular study we assume that the self selection chooses the relay that minimizes the remaining distance to the destination. This criterion requires that the nodes know their geographic positions. However, as we show, if only a small fraction of the nodes in the network know their positions exactly, e.g. using GPS, and provide this information to the remaining to nodes to let them estimate their positions, our proposed technique still works very well and outperforms conventional routing techniques.
{"title":"An optimized relay self selection technique for opportunistic routing in mobile ad hoc networks","authors":"F. Baccelli, B. Błaszczyszyn, Erwan Ermel, P. Mühlethaler","doi":"10.1109/EW.2008.4623843","DOIUrl":"https://doi.org/10.1109/EW.2008.4623843","url":null,"abstract":"In this paper we present a new routing technique which can operate on mobile ad hoc networks. This technique is opportunistic in the sense that each packet on its (specific) route from an origin (O) to a destination (D) at each hop takes advantage from the current pattern of nodes who captured its recent (retransmission to choose the next relay. Note that this is unlike in conventional routing protocols, which first predetermine the relays on a route from O to D, e.g. with a shortest path algorithm, and then let a given medium access (MAC) protocol, e.g. Carrier-Sense Multiple Access (CSMA), deliver all the packets using this route. Moreover, in our technique, the current transmitter of a given packet does not know its next relay a priori, but the nodes who capture this transmission (if any) perform a self selection to chose the unique packet relay node and acknowledge the transmitter. Finally, the above relay self selection procedure is optimized in the sense that it is the node that optimizes some given utility criterion, e.g. minimizes the remaining distance to D, which is chosen as the relay. The primary goal of this paper is to explain how relay self selection can be achieved. Moreover, we show that this routing technique works well with various MAC protocols which may be controlled multiple access schemes or random access schemes. More precisely, assuming two different MAC protocols: Aloha and CSMA, we use simulations to compare the performance of this new routing technique to conventional shortest path routing. In this particular study we assume that the self selection chooses the relay that minimizes the remaining distance to the destination. This criterion requires that the nodes know their geographic positions. However, as we show, if only a small fraction of the nodes in the network know their positions exactly, e.g. using GPS, and provide this information to the remaining to nodes to let them estimate their positions, our proposed technique still works very well and outperforms conventional routing techniques.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126315363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates the performance of the downlink in Multi Carrier CDMA (MC-CDMA) systems using a channel model from in-the-field propagation measurements. Results are presented also for channel models having non-exponentially decaying profiles. Channel coherence bandwidth (Bc) is incorporated within the analysis in order to demonstrate the effect of channel frequency selectivity on system performance. The effect of transmission bandwidth, number of users and number of sub-carriers on system performance is analyzed. Our simulation results show that Bc values for correlation coefficients of 0.75 or 0.9 can be used to represent the channel properties to investigate the required number of subcarriers. The level of multiple access interference is also shown to be related to the Bc value for correlation coefficient of 0.5. Performance was analyzed for transmission bandwidths of 20 MHz and 40 MHz. Our results show that for some channels, performance is improved by using narrower transmission bandwidth and by selecting the band of transmission within the available band.
{"title":"Investigating MC-CDMA system performance using measurement-based channel models","authors":"Ç. Kurnaz, H. Gökalp","doi":"10.1109/EW.2008.4623889","DOIUrl":"https://doi.org/10.1109/EW.2008.4623889","url":null,"abstract":"This paper investigates the performance of the downlink in Multi Carrier CDMA (MC-CDMA) systems using a channel model from in-the-field propagation measurements. Results are presented also for channel models having non-exponentially decaying profiles. Channel coherence bandwidth (Bc) is incorporated within the analysis in order to demonstrate the effect of channel frequency selectivity on system performance. The effect of transmission bandwidth, number of users and number of sub-carriers on system performance is analyzed. Our simulation results show that Bc values for correlation coefficients of 0.75 or 0.9 can be used to represent the channel properties to investigate the required number of subcarriers. The level of multiple access interference is also shown to be related to the Bc value for correlation coefficient of 0.5. Performance was analyzed for transmission bandwidths of 20 MHz and 40 MHz. Our results show that for some channels, performance is improved by using narrower transmission bandwidth and by selecting the band of transmission within the available band.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124178399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Hiertz, Sebastian Max, T. Junge, D. Denteneer, L. Berlemann
In 2003, interests in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 Working Group (WG) led to formation of Task Group (TG) ldquoSrdquo. 802.11s develops an amendment for wireless local area network (WLAN) mesh. Unlike existing WLAN mesh products, 802.11s forms a transparent 802 broadcast domain that supports any higher layer protocols. Therefore, 802.11s provides frame forwarding and path selection at layer-2. While traditional WLANs are access point (AP) centered, the WLAN mesh is fully distributed. Hence, 802.11s considers extensions to the medium access control (MAC) too. The current draft 2.0 of 802.11s denotes the optional MAC as mesh deterministic access (MDA). Due to the high amount of indirect neighbors in a WLAN mesh, the current single-hop medium access control mechanisms cannot operate efficiently. In contrast, unlike traditional listen-before-talk scheme MDApsilas advanced medium reservation scheme allows for operation free of collisions. Therefore, MDA enables support for quality of service (QoS) and provides more capacity in the WLAN mesh. In this paper, the authors, who have contributed to the standardization of 802.11s since 2003, give insight to the basics of draft 2.0 of 802.11s and its principles. Furthermore, we provide detailed simulation results of 802.11psilas first WLAN mesh aware MAC: MDA. Our simulation results show that unlike the traditional enhanced distributed channel access (EDCA), MDA does not stall when the offered traffic is high. Due to its planned medium access, limited packet delay can be achieved.
{"title":"IEEE 802.11s - Mesh Deterministic Access","authors":"G. Hiertz, Sebastian Max, T. Junge, D. Denteneer, L. Berlemann","doi":"10.1109/EW.2008.4623884","DOIUrl":"https://doi.org/10.1109/EW.2008.4623884","url":null,"abstract":"In 2003, interests in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 Working Group (WG) led to formation of Task Group (TG) ldquoSrdquo. 802.11s develops an amendment for wireless local area network (WLAN) mesh. Unlike existing WLAN mesh products, 802.11s forms a transparent 802 broadcast domain that supports any higher layer protocols. Therefore, 802.11s provides frame forwarding and path selection at layer-2. While traditional WLANs are access point (AP) centered, the WLAN mesh is fully distributed. Hence, 802.11s considers extensions to the medium access control (MAC) too. The current draft 2.0 of 802.11s denotes the optional MAC as mesh deterministic access (MDA). Due to the high amount of indirect neighbors in a WLAN mesh, the current single-hop medium access control mechanisms cannot operate efficiently. In contrast, unlike traditional listen-before-talk scheme MDApsilas advanced medium reservation scheme allows for operation free of collisions. Therefore, MDA enables support for quality of service (QoS) and provides more capacity in the WLAN mesh. In this paper, the authors, who have contributed to the standardization of 802.11s since 2003, give insight to the basics of draft 2.0 of 802.11s and its principles. Furthermore, we provide detailed simulation results of 802.11psilas first WLAN mesh aware MAC: MDA. Our simulation results show that unlike the traditional enhanced distributed channel access (EDCA), MDA does not stall when the offered traffic is high. Due to its planned medium access, limited packet delay can be achieved.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131143907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we derive simple and asymptotically tight expressions for the pairwise error probability (PEP) of coherent space-time codes (STCs) which are valid for any type of noise and interference with finite moments and detection with general Mahalonobis distance (MD) metrics including Euclidean distance (ED) and noise decorrelating (ND) metric. We show that while the diversity gain of an STC is independent of the type of noise and the type of MD metric used, the coding gain depends on both the noise distribution and the MD metric. We show that in the case of correlated noise, significant performance gains can be achieved with the ND metric compared to the ED metric. While noise correlations are beneficial at high signal-to-noise ratios if they can be exploited by the metric, they are harmful if this is not the case and the simple ED metric is employed.
{"title":"Asymptotic analysis of space-time codes with Mahalonobis distance decoding in non-gaussian noise and interference","authors":"A. Nezampour, R. Schober, Yao Ma","doi":"10.1109/EW.2008.4623873","DOIUrl":"https://doi.org/10.1109/EW.2008.4623873","url":null,"abstract":"In this paper, we derive simple and asymptotically tight expressions for the pairwise error probability (PEP) of coherent space-time codes (STCs) which are valid for any type of noise and interference with finite moments and detection with general Mahalonobis distance (MD) metrics including Euclidean distance (ED) and noise decorrelating (ND) metric. We show that while the diversity gain of an STC is independent of the type of noise and the type of MD metric used, the coding gain depends on both the noise distribution and the MD metric. We show that in the case of correlated noise, significant performance gains can be achieved with the ND metric compared to the ED metric. While noise correlations are beneficial at high signal-to-noise ratios if they can be exploited by the metric, they are harmful if this is not the case and the simple ED metric is employed.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114733762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Danil Kipnis, A. Willig, Jan-Hinrich Hauer, Niels Karowski
The EU FP6 ANGEL project considers the usage of IEEE 802.15.4-based wireless sensor network technology in medical applications. Some key requirements found in this class of applications are not well supported by IEEE 802.15.4. In this paper we propose a wrapper layer on top of IEEE 802.15.4 that adds, amongst others, a mechanism combining priority queueing and per-packet parameter control to provide (stochastic) service differentiation. In this paper we describe the design and implementation of this mechanism and present measurement results, showing its effectiveness.
EU FP6 ANGEL项目考虑在医疗应用中使用基于IEEE 802.15.4的无线传感器网络技术。在这类应用程序中发现的一些关键需求不被IEEE 802.15.4很好地支持。在本文中，我们在IEEE 802.15.4之上提出了一个包装层，该层添加了一种结合优先级队列和每包参数控制的机制，以提供(随机)服务差异化。本文描述了该机制的设计和实现，并给出了测试结果，证明了该机制的有效性。
{"title":"The ANGEL IEEE 802.15.4 enhancement layer: Coupling priority queueing and service differentiation","authors":"Danil Kipnis, A. Willig, Jan-Hinrich Hauer, Niels Karowski","doi":"10.1109/EW.2008.4623895","DOIUrl":"https://doi.org/10.1109/EW.2008.4623895","url":null,"abstract":"The EU FP6 ANGEL project considers the usage of IEEE 802.15.4-based wireless sensor network technology in medical applications. Some key requirements found in this class of applications are not well supported by IEEE 802.15.4. In this paper we propose a wrapper layer on top of IEEE 802.15.4 that adds, amongst others, a mechanism combining priority queueing and per-packet parameter control to provide (stochastic) service differentiation. In this paper we describe the design and implementation of this mechanism and present measurement results, showing its effectiveness.","PeriodicalId":237850,"journal":{"name":"2008 14th European Wireless Conference","volume":"285 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116107100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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