Pub Date : 2016-09-18DOI: 10.1109/VTCFall.2016.7881245
Daehee Park, D. Cho
A single-RF transmitter based on repetitive pulse width modulation (RPWM) was proposed for an alternative system of multiple-input multiple- output (MIMO) system. However, the RPWM transmitter system has a demerit in view of requiring twice the number of antenna elements than the conventional MIMO transmitter. Then we propose an advanced RPWM transmitter which requires the same number of antenna elements compared to the conventional MIMO transmitter in this paper. We also verify that the proposed RPWM transmitter achieves similar multiplexing gain compared to the conventional MIMO system.
{"title":"Switch Control Based Single-RF Transmitter for Multiplexing Gain","authors":"Daehee Park, D. Cho","doi":"10.1109/VTCFall.2016.7881245","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7881245","url":null,"abstract":"A single-RF transmitter based on repetitive pulse width modulation (RPWM) was proposed for an alternative system of multiple-input multiple- output (MIMO) system. However, the RPWM transmitter system has a demerit in view of requiring twice the number of antenna elements than the conventional MIMO transmitter. Then we propose an advanced RPWM transmitter which requires the same number of antenna elements compared to the conventional MIMO transmitter in this paper. We also verify that the proposed RPWM transmitter achieves similar multiplexing gain compared to the conventional MIMO system.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89957735","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}
Pub Date : 2016-09-18DOI: 10.1109/VTCFall.2016.7881016
Mohamed Nacer Bouatit, S. Boumerdassi, P. Minet, Adel Djama
The various reasons of failures that affect reliability of sensor nodes in addition to processing and transfer of large multimedia content (image, audio and video) have posed new challenges that are nowadays a real threat for routing protocols in Wireless Multimedia Sensor Networks (WMSNs), which aim to ensure flow delivery while guaranteeing QoS requirements. Moreover, extending network lifetime and maintaining network stability to cope with breaking links and topology changes (failures or sensor mobility), remain unsolved issues, particularly, during data transmission phase. Therefore, in this paper, we jointly consider multipath transmission, load balancing and fault tolerance, to enhance the reliability of transmitted data. We propose a Geographic Multipath routing protocol reinforced by Fault-Tolerant mechanism (GMFT). Theoricals results and those obtained from both simulation study and experiments on a real testbed demonstrate the validity and efficiency of our proposed protocol, and indicate that it is highly advised for multimedia transmission and network stability.
{"title":"Fault-Tolerant Mechanism for Multimedia Transmission in Wireless Sensor Networks","authors":"Mohamed Nacer Bouatit, S. Boumerdassi, P. Minet, Adel Djama","doi":"10.1109/VTCFall.2016.7881016","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7881016","url":null,"abstract":"The various reasons of failures that affect reliability of sensor nodes in addition to processing and transfer of large multimedia content (image, audio and video) have posed new challenges that are nowadays a real threat for routing protocols in Wireless Multimedia Sensor Networks (WMSNs), which aim to ensure flow delivery while guaranteeing QoS requirements. Moreover, extending network lifetime and maintaining network stability to cope with breaking links and topology changes (failures or sensor mobility), remain unsolved issues, particularly, during data transmission phase. Therefore, in this paper, we jointly consider multipath transmission, load balancing and fault tolerance, to enhance the reliability of transmitted data. We propose a Geographic Multipath routing protocol reinforced by Fault-Tolerant mechanism (GMFT). Theoricals results and those obtained from both simulation study and experiments on a real testbed demonstrate the validity and efficiency of our proposed protocol, and indicate that it is highly advised for multimedia transmission and network stability.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76260459","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}
Pub Date : 2016-09-18DOI: 10.1109/VTCFall.2016.7880920
T. Le, K. Navaie, Quoc-Tuan Vien, H. Nguyen
This paper considers an underlay access strategy for coexisting wireless networks where the secondary system utilizes the primary spectrum to serve its users. We focus on the practical cases where there is uncertainty in the estimation of channel state information (CSI). Here the throughput performance of each system is limited by the interference imposed by the other, resulting in conflicting objectives. We first analyze the fundamental tradeoff between the tolerance interference level at the primary system and the total achievable throughput of the secondary users. We then introduce a beamforming design problem as a multiobjective optimization to minimize the interference imposed on each of the primary users while maximizing the intended signal received at every secondary user, taking into account the CSI uncertainty. We then map the proposed optimization problem to a robust counterpart under the maximum CSI estimation error. The robust counterpart is then transformed into a standard convex semi-definite programming. Simulation results confirm the effectiveness of the proposed scheme against various levels of CSI estimation error. We further show that in the proposed approach, the trade-off in the two systems modelled by Pareto frontier can be engineered by adjusting system parameters. For instance, the simulations show that at the primary system interference thresholds of -10 dBm (-5 dBm) by increasing number of antennas from 4 to 12, the secondary system throughput is increased by 3.3 bits/s/channel-use (5.3 bits/s/channel-use).
{"title":"Beamforming in Coexisting Wireless Systems with Uncertain Channel State Information","authors":"T. Le, K. Navaie, Quoc-Tuan Vien, H. Nguyen","doi":"10.1109/VTCFall.2016.7880920","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7880920","url":null,"abstract":"This paper considers an underlay access strategy for coexisting wireless networks where the secondary system utilizes the primary spectrum to serve its users. We focus on the practical cases where there is uncertainty in the estimation of channel state information (CSI). Here the throughput performance of each system is limited by the interference imposed by the other, resulting in conflicting objectives. We first analyze the fundamental tradeoff between the tolerance interference level at the primary system and the total achievable throughput of the secondary users. We then introduce a beamforming design problem as a multiobjective optimization to minimize the interference imposed on each of the primary users while maximizing the intended signal received at every secondary user, taking into account the CSI uncertainty. We then map the proposed optimization problem to a robust counterpart under the maximum CSI estimation error. The robust counterpart is then transformed into a standard convex semi-definite programming. Simulation results confirm the effectiveness of the proposed scheme against various levels of CSI estimation error. We further show that in the proposed approach, the trade-off in the two systems modelled by Pareto frontier can be engineered by adjusting system parameters. For instance, the simulations show that at the primary system interference thresholds of -10 dBm (-5 dBm) by increasing number of antennas from 4 to 12, the secondary system throughput is increased by 3.3 bits/s/channel-use (5.3 bits/s/channel-use).","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78561384","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}
Pub Date : 2016-09-18DOI: 10.1109/VTCFall.2016.7880880
R. Xu, L. Lei, Xiong Xiong, K. Zheng, Hengyang Shen
The IEEE 802.15.4k standard has defined the phys- ical and multiple media access (MAC) layer for low-energy critical infrastructure monitoring (LECIM) networks, which can be used to monitor infrastructure facilities including industrial metering. The main features of LECIM networks are minimal infrastructure with star topology, long range communication with high receiver sensitivity, very limited energy supplied devices. Based on IEEE 802.15.4k specifications, we have designed and developed the prototypes of end device (ED) and access point (AP) using software defined radio technology. The end device is implemented with an ARM-based MCU and a RF module, while the access point is realized by GNURadio and universal software radio peripheral (USRP). A novel parallel preamble and payload detection is applied at AP to acquire multiple packets from respective ED instead of collision avoidance. Furthermore, the field trails are conducted in urban area to demonstrate and evaluate the effectiveness of testbed design.
{"title":"A Software Defined Radio Based IEEE 802.15.4k Testbed for M2M Applications","authors":"R. Xu, L. Lei, Xiong Xiong, K. Zheng, Hengyang Shen","doi":"10.1109/VTCFall.2016.7880880","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7880880","url":null,"abstract":"The IEEE 802.15.4k standard has defined the phys- ical and multiple media access (MAC) layer for low-energy critical infrastructure monitoring (LECIM) networks, which can be used to monitor infrastructure facilities including industrial metering. The main features of LECIM networks are minimal infrastructure with star topology, long range communication with high receiver sensitivity, very limited energy supplied devices. Based on IEEE 802.15.4k specifications, we have designed and developed the prototypes of end device (ED) and access point (AP) using software defined radio technology. The end device is implemented with an ARM-based MCU and a RF module, while the access point is realized by GNURadio and universal software radio peripheral (USRP). A novel parallel preamble and payload detection is applied at AP to acquire multiple packets from respective ED instead of collision avoidance. Furthermore, the field trails are conducted in urban area to demonstrate and evaluate the effectiveness of testbed design.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81586089","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}
Pub Date : 2016-09-01DOI: 10.1109/VTCFall.2016.7880894
Yi Jiang, Ruonan Zhang, Wei Cheng, Bin Li, Wei Sun
Tag collision occurs easily when the multiple tags respond to the same reader query simultaneously over a shared wireless channel. The solution of tag collision is a significant issue in the mobile RFID environment, because of the random mobility of tags. For the purpose of object tracking, locating and monitoring, the reader will repeatedly identify the same tags which still stay within its read range, which will waste a lot of resources and add some new collisions. To handle the above case well, we propose a tag anti-collision protocol based on adaptive ternary query splitting (ATQS), which can effectively avoid the collisions between the new arriving tags and the original staying tags by the blocking technique. Using the formula for the conversion of binary to ternary, the number and length of queries are simplified by a ternary query tree. Using the ternary resolution technique, the new processing procedure of tag identification is designed, in which the reader can use only one prefix of ID to identify at most three staying tags having the same prefix. From the simulation and performance analysis, it obtains that our protocol can effectively decrease the identification delay, which outperforms the previous protocols with the impacts of the staying ratio, the arriving radio and the number of tags.
{"title":"An Adaptive Ternary Query Splitting Based Tag Anti-Collision Protocol for Mobile RFID Systems","authors":"Yi Jiang, Ruonan Zhang, Wei Cheng, Bin Li, Wei Sun","doi":"10.1109/VTCFall.2016.7880894","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7880894","url":null,"abstract":"Tag collision occurs easily when the multiple tags respond to the same reader query simultaneously over a shared wireless channel. The solution of tag collision is a significant issue in the mobile RFID environment, because of the random mobility of tags. For the purpose of object tracking, locating and monitoring, the reader will repeatedly identify the same tags which still stay within its read range, which will waste a lot of resources and add some new collisions. To handle the above case well, we propose a tag anti-collision protocol based on adaptive ternary query splitting (ATQS), which can effectively avoid the collisions between the new arriving tags and the original staying tags by the blocking technique. Using the formula for the conversion of binary to ternary, the number and length of queries are simplified by a ternary query tree. Using the ternary resolution technique, the new processing procedure of tag identification is designed, in which the reader can use only one prefix of ID to identify at most three staying tags having the same prefix. From the simulation and performance analysis, it obtains that our protocol can effectively decrease the identification delay, which outperforms the previous protocols with the impacts of the staying ratio, the arriving radio and the number of tags.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73457842","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}
Pub Date : 2016-09-01DOI: 10.1109/VTCFall.2016.7880919
Xiaoxu Zhang, Ying-Chang Liang, Jun Fang
Machine-to-Machine (M2M) communications will be playing an important role in the development of 5th generation (5G) and future wireless communication systems. Due to the sporadic nature of massive access, Low-Activity Code Division Multiple Access (LA-CDMA) is one of possible multiple access schemes for M2M communications. In the literature, maximum a posterior (MAP) detector has been proposed to detect the active users when the user activity factor is known and small. However, the user activity factor is usually unknown and could be large in practice, which makes the multiuser detection (MUD) a challenging task for LA-CDMA. In this paper, we first introduce sparse Bayesian learning (SBL) method to recover the transmitted signals for LA- CDMA uplink access. The proposed method exploits the sparsity of the transmitted signals and does not require the knowledge of user activity. Furthermore, we add on the known finite-alphabet constraints and introduce Gaussian mixture model (GMM) method to obtain the transmitted signals. Simulation results have shown that the proposed methods outperform the conventional algorithms.
{"title":"Bayesian Inference Algorithms for Multiuser Detection in M2M Communications","authors":"Xiaoxu Zhang, Ying-Chang Liang, Jun Fang","doi":"10.1109/VTCFall.2016.7880919","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7880919","url":null,"abstract":"Machine-to-Machine (M2M) communications will be playing an important role in the development of 5th generation (5G) and future wireless communication systems. Due to the sporadic nature of massive access, Low-Activity Code Division Multiple Access (LA-CDMA) is one of possible multiple access schemes for M2M communications. In the literature, maximum a posterior (MAP) detector has been proposed to detect the active users when the user activity factor is known and small. However, the user activity factor is usually unknown and could be large in practice, which makes the multiuser detection (MUD) a challenging task for LA-CDMA. In this paper, we first introduce sparse Bayesian learning (SBL) method to recover the transmitted signals for LA- CDMA uplink access. The proposed method exploits the sparsity of the transmitted signals and does not require the knowledge of user activity. Furthermore, we add on the known finite-alphabet constraints and introduce Gaussian mixture model (GMM) method to obtain the transmitted signals. Simulation results have shown that the proposed methods outperform the conventional algorithms.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73793098","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}
Pub Date : 2016-09-01DOI: 10.1109/VTCFall.2016.7881041
Shady O. Elbassiouny, A. Elezabi
3G systems, which are expected to still be widely deployed over the next decade, utilize Direct-Sequence Code-Division Multiple-Access (DS-CDMA) which suffers mainly from the Multiple Access Interference (MAI). This paper proposes improved decoder log-likelihood ratios for the practical uplink. The basic idea is to utilize knowledge about user cross-correlations and fading coefficients to obtain conditional variances for the MAI, rather than to conventionally assume it to be Gaussian with fixed variance. The conditioning may be on the users' cross-correlations and/or the channel fading coefficients and results in a time-dependent variance. We present improved log-likelihood ratios (ILLRs) for the chip synchronous case, and derive the ILLRs for the chip-asynchronous multi-path fading channel and the raised-cosine transmit filter. Our simulation framework applies system parameters from 3G standards. The improvements for the synchronous case are much larger, as expected. However, even in the practical case of cellular uplink, the performance advantage due to ILLRs is significant approaching 3 dB.
{"title":"Improved Decoder Likelihoods for 3G Cellular Uplink over Asynchronous Multi-Path Fading Channels","authors":"Shady O. Elbassiouny, A. Elezabi","doi":"10.1109/VTCFall.2016.7881041","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7881041","url":null,"abstract":"3G systems, which are expected to still be widely deployed over the next decade, utilize Direct-Sequence Code-Division Multiple-Access (DS-CDMA) which suffers mainly from the Multiple Access Interference (MAI). This paper proposes improved decoder log-likelihood ratios for the practical uplink. The basic idea is to utilize knowledge about user cross-correlations and fading coefficients to obtain conditional variances for the MAI, rather than to conventionally assume it to be Gaussian with fixed variance. The conditioning may be on the users' cross-correlations and/or the channel fading coefficients and results in a time-dependent variance. We present improved log-likelihood ratios (ILLRs) for the chip synchronous case, and derive the ILLRs for the chip-asynchronous multi-path fading channel and the raised-cosine transmit filter. Our simulation framework applies system parameters from 3G standards. The improvements for the synchronous case are much larger, as expected. However, even in the practical case of cellular uplink, the performance advantage due to ILLRs is significant approaching 3 dB.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73924825","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}
Pub Date : 2016-09-01DOI: 10.1109/VTCFall.2016.7881204
Che-Tsung Lin, Long-Tai Chen, Pai-Wei Cheng, Yuan-fang Wang
Advances in video technology have enabled its wide adoption in the auto industry. Today, many vehicles are equipped with backup, front-looking, and side-looking cameras that allow the driver to easily monitor traffic around the vehicle for enhancing safety. One difficulty with performing automated image analysis using a vehicle's onboard video has to do with the significant lens distortion of these sensors to cover a large field of view around the vehicle. This paper reports our research on proposing a tracking scheme that improves the accuracy and denseness of object tracking in the presence of large lens distortion. The contribution of our research is 4-fold: (1) We evaluated a large collection of state-of-the-art trackers to understand their deficiency when applied to videos with large lens distortion, (2) we showed how to derive useful evaluation metrics from public-domain, real-world driving videos that do not come with ground-truth information on pixel tracking, (3) we identified many enhancement techniques that can potentially help improve the poor performance of current trackers on videos of large lens distortion, and (4) we performed a systematic study to validate the efficacy of these enhancement techniques and proposed a new tracker design that achieved substantial improvement over the state-of-the- art, in terms of both accuracy and density, based on a rigorous precision vs. recall analysis.
{"title":"Robust and Efficient Tracking with Large Lens Distortion for Vehicular Technology Applications","authors":"Che-Tsung Lin, Long-Tai Chen, Pai-Wei Cheng, Yuan-fang Wang","doi":"10.1109/VTCFall.2016.7881204","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7881204","url":null,"abstract":"Advances in video technology have enabled its wide adoption in the auto industry. Today, many vehicles are equipped with backup, front-looking, and side-looking cameras that allow the driver to easily monitor traffic around the vehicle for enhancing safety. One difficulty with performing automated image analysis using a vehicle's onboard video has to do with the significant lens distortion of these sensors to cover a large field of view around the vehicle. This paper reports our research on proposing a tracking scheme that improves the accuracy and denseness of object tracking in the presence of large lens distortion. The contribution of our research is 4-fold: (1) We evaluated a large collection of state-of-the-art trackers to understand their deficiency when applied to videos with large lens distortion, (2) we showed how to derive useful evaluation metrics from public-domain, real-world driving videos that do not come with ground-truth information on pixel tracking, (3) we identified many enhancement techniques that can potentially help improve the poor performance of current trackers on videos of large lens distortion, and (4) we performed a systematic study to validate the efficacy of these enhancement techniques and proposed a new tracker design that achieved substantial improvement over the state-of-the- art, in terms of both accuracy and density, based on a rigorous precision vs. recall analysis.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75838256","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}
Pub Date : 2016-09-01DOI: 10.1109/VTCFall.2016.7881158
M. Khoshkholgh, K. Navaie, K. Shin, Victor C. M. Leung
In this paper adopting stochastic geometry we investigate the system performance in heterogenous networks including multiple tiers of BSs with multiple-input single output spatial division multiple access (MISO-SDMA) technique. In the related literature on heterogenous systems, ideal cell association (CA) rules are often considered for simplicity, where each user equipment (UE) examines a very large number of pilots across the tiers before choosing its associated base station (BS). Here we consider practical cases where UEs are restricted to examine $K_H geq 1$ pilots across all tiers before choosing their associated BS. We then obtain closed-form expressions for the system performance measured by the coverage probability and UE's data rate. Our analytical results provide quantitative insights on the impact of different factors on the system performance including the BS's spatial density, their transmission powers, number of transmit antennas, SIR thresholds, number of UEs served by each BS, and $K_H$. Interestingly, we observe that increasing $K_H$ always improves the coverage probability however, it only improves data rate up to a certain point. The data rate is then reduced by further increasing of $K_H$. Given $K_H$ pilots in practical cases, the issue is how to allocate the pilots among different tiers. We address this issue by developing an algorithm and show that by careful allocation of available pilots, the network performance is significantly improved even in cases with small $K_H$. Our results also indicate a fundamental tradeoff, as sharing strategies providing the best coverage performance yield very poor capacity and vice versa. Such trade-off provides a new degree of freedom in heterogeneous networks design.
{"title":"Performance Evaluation of MISO-SDMA in Heterogeneous Networks with Practical Cell Association","authors":"M. Khoshkholgh, K. Navaie, K. Shin, Victor C. M. Leung","doi":"10.1109/VTCFall.2016.7881158","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7881158","url":null,"abstract":"In this paper adopting stochastic geometry we investigate the system performance in heterogenous networks including multiple tiers of BSs with multiple-input single output spatial division multiple access (MISO-SDMA) technique. In the related literature on heterogenous systems, ideal cell association (CA) rules are often considered for simplicity, where each user equipment (UE) examines a very large number of pilots across the tiers before choosing its associated base station (BS). Here we consider practical cases where UEs are restricted to examine $K_H geq 1$ pilots across all tiers before choosing their associated BS. We then obtain closed-form expressions for the system performance measured by the coverage probability and UE's data rate. Our analytical results provide quantitative insights on the impact of different factors on the system performance including the BS's spatial density, their transmission powers, number of transmit antennas, SIR thresholds, number of UEs served by each BS, and $K_H$. Interestingly, we observe that increasing $K_H$ always improves the coverage probability however, it only improves data rate up to a certain point. The data rate is then reduced by further increasing of $K_H$. Given $K_H$ pilots in practical cases, the issue is how to allocate the pilots among different tiers. We address this issue by developing an algorithm and show that by careful allocation of available pilots, the network performance is significantly improved even in cases with small $K_H$. Our results also indicate a fundamental tradeoff, as sharing strategies providing the best coverage performance yield very poor capacity and vice versa. Such trade-off provides a new degree of freedom in heterogeneous networks design.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74528033","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}
Pub Date : 2016-09-01DOI: 10.1109/VTCFall.2016.7881059
V. Mai, A. Pham
This paper proposes a novel operation for hybrid Free Space Optics (FSO)/Radio Frequency (RF) systems. We add a new function to current hybrid systems, which is responsible for operation mode selection (OMS). A dynamic OMS policy is proposed by taking intelligent control decisions at the transmitter taking into account states of both queue and channel (i.e. queue-aware and channel- aware). System performance metrics are analytically studied based on a combination of queuing and Markov chain theories. Numerical results quantitatively show how the proposed operation outperforms the conventional ones.
{"title":"Joint Queue-Aware and Channel-Aware for a Novel Operation of Hybrid FSO/RF Systems","authors":"V. Mai, A. Pham","doi":"10.1109/VTCFall.2016.7881059","DOIUrl":"https://doi.org/10.1109/VTCFall.2016.7881059","url":null,"abstract":"This paper proposes a novel operation for hybrid Free Space Optics (FSO)/Radio Frequency (RF) systems. We add a new function to current hybrid systems, which is responsible for operation mode selection (OMS). A dynamic OMS policy is proposed by taking intelligent control decisions at the transmitter taking into account states of both queue and channel (i.e. queue-aware and channel- aware). System performance metrics are analytically studied based on a combination of queuing and Markov chain theories. Numerical results quantitatively show how the proposed operation outperforms the conventional ones.","PeriodicalId":6484,"journal":{"name":"2016 IEEE 84th Vehicular Technology Conference (VTC-Fall)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74719426","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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