Pub Date : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120501
Suresh Singh, T. Le, H. Tran
This paper examines the performance of a 2x2 Line of Sight (LoS) Multiple Input Multiple Output (MIMO) channel at three terahertz frequencies-340 GHz, 410 Ghz, and 460 GHz. While theoretical models predict very high channel capacities, we observe lower capacity which is explained by asymmetric transmit-to-receive signal strengths as well as due to signal attenuation over longer distances. Overall, however, we note that at 460 Ghz, channel capacity of higher than 12 bps/hz is possible even at sub-optimal inter-antenna spacings (for different distances). An important observation is also that we need to maintain appropriate receive signal levels at receive antennas in order to improve capacity.
{"title":"Measurement of 2x2 LoS Terahertz MIMO Channel","authors":"Suresh Singh, T. Le, H. Tran","doi":"10.1109/WCNC45663.2020.9120501","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120501","url":null,"abstract":"This paper examines the performance of a 2x2 Line of Sight (LoS) Multiple Input Multiple Output (MIMO) channel at three terahertz frequencies-340 GHz, 410 Ghz, and 460 GHz. While theoretical models predict very high channel capacities, we observe lower capacity which is explained by asymmetric transmit-to-receive signal strengths as well as due to signal attenuation over longer distances. Overall, however, we note that at 460 Ghz, channel capacity of higher than 12 bps/hz is possible even at sub-optimal inter-antenna spacings (for different distances). An important observation is also that we need to maintain appropriate receive signal levels at receive antennas in order to improve capacity.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121799946","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120815
C. Jans, Xiaohang Song, W. Rave, G. Fettweis
This work focuses on the initial beam acquisition/alignment of millimeter wave (mmWave) communication systems. To detect the angle of arrival (AoA) and/or angle of departure (AoD), we propose a training protocol which probes all beamformers from a given codebook simultaneously by exploiting the sparse nature of mmWave channels. By applying a frequency-selective beam probing network, we can map each beamformer from the codebook to different frequencies and a spectral analysis at the receiver allows us to deduce favorable beamformers or AoDs. For practical reasons, we elaborate this idea of steering direction to frequency mapping for an orthogonal frequency division multiplexing (OFDM) communication system, i.e., we map each beamformer to specific pilot subcarriers. Under two different hardware designs, we investigate the feasibility of building such beamformer to frequency mappings for one additional radio frequency (RF) chain next to an existing OFDM communication system. We show that parallel beam training is able to achieve better effective transmission rates than exhaustive search in fast-time varying environments due to high temporal efficiency. This is crucial for mmWave communication systems which have access to large beamforming codebooks but suffer from short coherence times due to mobility and high spatial resolution.
{"title":"Frequency-Selective Analog Beam Probing for Millimeter Wave Communication Systems","authors":"C. Jans, Xiaohang Song, W. Rave, G. Fettweis","doi":"10.1109/WCNC45663.2020.9120815","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120815","url":null,"abstract":"This work focuses on the initial beam acquisition/alignment of millimeter wave (mmWave) communication systems. To detect the angle of arrival (AoA) and/or angle of departure (AoD), we propose a training protocol which probes all beamformers from a given codebook simultaneously by exploiting the sparse nature of mmWave channels. By applying a frequency-selective beam probing network, we can map each beamformer from the codebook to different frequencies and a spectral analysis at the receiver allows us to deduce favorable beamformers or AoDs. For practical reasons, we elaborate this idea of steering direction to frequency mapping for an orthogonal frequency division multiplexing (OFDM) communication system, i.e., we map each beamformer to specific pilot subcarriers. Under two different hardware designs, we investigate the feasibility of building such beamformer to frequency mappings for one additional radio frequency (RF) chain next to an existing OFDM communication system. We show that parallel beam training is able to achieve better effective transmission rates than exhaustive search in fast-time varying environments due to high temporal efficiency. This is crucial for mmWave communication systems which have access to large beamforming codebooks but suffer from short coherence times due to mobility and high spatial resolution.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121820162","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120470
Y. Zou, Yutong Xie, Canhui Zhang, Shimin Gong, D. Hoang, D. Niyato
In this paper, we employ multiple wireless-powered user devices as wireless relays to assist information transmission from a multi-antenna access point to a single-antenna receiver. To improve energy efficiency, we design a hybrid relaying communication strategy in which wireless relays are allowed to operate in either the passive mode via backscatter communications or the active mode via RF communications, depending on their channel conditions and energy states. We aim to maximize the overall SNR by jointly optimizing the access point’s beamforming strategy as well as individual relays’ radio modes and operating parameters. Due to the non-convex and combinatorial structure of the SNR maximization problem, we develop a deep reinforcement learning approach that adapts the beamforming and relaying strategies dynamically. In particular, we propose a novel optimization-driven hierarchical deep deterministic policy gradient (H-DDPG) approach that integrates the model-based optimization into the framework of conventional DDPG approach. It decomposes the discrete relay mode selection into the outer-loop by using deep Q-network (DQN) algorithm and then optimizes the continuous beamforming and relays’ operating parameters by using the inner-loop DDPG algorithm. Simulation results reveal that the H-DDPG is robust to the hyper parameters and can speed up the learning process compared to the conventional DDPG approach.
{"title":"Optimization-driven Hierarchical Deep Reinforcement Learning for Hybrid Relaying Communications","authors":"Y. Zou, Yutong Xie, Canhui Zhang, Shimin Gong, D. Hoang, D. Niyato","doi":"10.1109/WCNC45663.2020.9120470","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120470","url":null,"abstract":"In this paper, we employ multiple wireless-powered user devices as wireless relays to assist information transmission from a multi-antenna access point to a single-antenna receiver. To improve energy efficiency, we design a hybrid relaying communication strategy in which wireless relays are allowed to operate in either the passive mode via backscatter communications or the active mode via RF communications, depending on their channel conditions and energy states. We aim to maximize the overall SNR by jointly optimizing the access point’s beamforming strategy as well as individual relays’ radio modes and operating parameters. Due to the non-convex and combinatorial structure of the SNR maximization problem, we develop a deep reinforcement learning approach that adapts the beamforming and relaying strategies dynamically. In particular, we propose a novel optimization-driven hierarchical deep deterministic policy gradient (H-DDPG) approach that integrates the model-based optimization into the framework of conventional DDPG approach. It decomposes the discrete relay mode selection into the outer-loop by using deep Q-network (DQN) algorithm and then optimizes the continuous beamforming and relays’ operating parameters by using the inner-loop DDPG algorithm. Simulation results reveal that the H-DDPG is robust to the hyper parameters and can speed up the learning process compared to the conventional DDPG approach.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121006281","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120684
S. Mukherjee, Dongsun Kim, Hewon Cho, Jemin Lee
In this paper, we propose a novel coordinated multipoint (CoMP) downlink transmission strategy for the ultra-dense network (UDN) environment. In this proposed CoMP transmission scheme, we exploit the average received link power (ARLP) of the base stations (BSs) with respect to the ARLP of the strongest BS to a typical user, to dynamically adjust the number of cooperating BSs serving that user in the network. This allows us to effectively manage the inter-cell interference in the UDN regime. Our numerical results and simulations show that the proposed scheme can out-perform the existing fixed number of BS based CoMP transmission scheme in the high BS density scenario.
{"title":"A Novel Coordinated Multi-point Downlink Transmission Scheme for Ultra-dense Networks","authors":"S. Mukherjee, Dongsun Kim, Hewon Cho, Jemin Lee","doi":"10.1109/WCNC45663.2020.9120684","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120684","url":null,"abstract":"In this paper, we propose a novel coordinated multipoint (CoMP) downlink transmission strategy for the ultra-dense network (UDN) environment. In this proposed CoMP transmission scheme, we exploit the average received link power (ARLP) of the base stations (BSs) with respect to the ARLP of the strongest BS to a typical user, to dynamically adjust the number of cooperating BSs serving that user in the network. This allows us to effectively manage the inter-cell interference in the UDN regime. Our numerical results and simulations show that the proposed scheme can out-perform the existing fixed number of BS based CoMP transmission scheme in the high BS density scenario.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124766086","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120565
Kanghua Chen, Ying Wang, Zixuan Fei, Xue Wang
Ultra-reliable and low-latency communication (URLLC) is proposed as one of the three key services of 5G for Internet of Things (IoT), especially for mission-critical applications. This paper investigates the minimum power of devices in uplink in IoT networks for URLLC. Unmanned aerial vehicles (UAVs) are utilized to assistant the IoT system because they have flexible deployment and high probability to establish line-of-sight (LoS) communication links. First, we formulate a minimum average transmit power problem under the constraints of latency and reliability in modern industry. The deployment of UAVs and device association need to be jointly optimized, making the problem non-linear and non-convex. Then the block error probability which characterizes the reliability is derived under finite blocklength regime and an iteration algorithm is proposed. Additionally, the minimum average transmit power of IoT devices in URLLC is also calculated by deploying different number of UAVs. Simulation results are presented to show that the transmit power can be greatly reduced by appropriately deploying more UAVs or relaxing the tolerance of latency.
{"title":"Power Limited Ultra-Reliable and Low-Latency Communication in UAV-Enabled IoT Networks","authors":"Kanghua Chen, Ying Wang, Zixuan Fei, Xue Wang","doi":"10.1109/WCNC45663.2020.9120565","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120565","url":null,"abstract":"Ultra-reliable and low-latency communication (URLLC) is proposed as one of the three key services of 5G for Internet of Things (IoT), especially for mission-critical applications. This paper investigates the minimum power of devices in uplink in IoT networks for URLLC. Unmanned aerial vehicles (UAVs) are utilized to assistant the IoT system because they have flexible deployment and high probability to establish line-of-sight (LoS) communication links. First, we formulate a minimum average transmit power problem under the constraints of latency and reliability in modern industry. The deployment of UAVs and device association need to be jointly optimized, making the problem non-linear and non-convex. Then the block error probability which characterizes the reliability is derived under finite blocklength regime and an iteration algorithm is proposed. Additionally, the minimum average transmit power of IoT devices in URLLC is also calculated by deploying different number of UAVs. Simulation results are presented to show that the transmit power can be greatly reduced by appropriately deploying more UAVs or relaxing the tolerance of latency.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126135316","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120683
P. Zhang, F. Lau, Chiu-Wing Sham
We propose a novel type of ultimate-Shannon-limit-approaching codes, namely protograph-based low-density parity-check Hadamard (PLDPC-Hadamard) codes in this paper. We also propose a systematic way of analyzing such codes using Protograph EXtrinsic Information Transfer (PEXIT) charts. Using the analytical technique we have found a code of rate about 0.05 having a theoretical threshold of -1.42dB. At a BER of $10^{-5}$, the gaps of our code to the Shannon capacity for R=0.05 and to the ultimate Shannon limit are 0.25 dB and 0.40 dB, respectively.
{"title":"Protograph-based LDPC-Hadamard Codes","authors":"P. Zhang, F. Lau, Chiu-Wing Sham","doi":"10.1109/WCNC45663.2020.9120683","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120683","url":null,"abstract":"We propose a novel type of ultimate-Shannon-limit-approaching codes, namely protograph-based low-density parity-check Hadamard (PLDPC-Hadamard) codes in this paper. We also propose a systematic way of analyzing such codes using Protograph EXtrinsic Information Transfer (PEXIT) charts. Using the analytical technique we have found a code of rate about 0.05 having a theoretical threshold of -1.42dB. At a BER of $10^{-5}$, the gaps of our code to the Shannon capacity for R=0.05 and to the ultimate Shannon limit are 0.25 dB and 0.40 dB, respectively.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"512 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123248581","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120818
Andreas Ingo Grohmann, Frank Gabriel, Sandra Zimmermann, F. Fitzek
Wireless networks have to support an increasing number of devices with increasing demands on mobility and resilience. Mesh network routing protocols provide an elegant solution to the problem of connecting mobile nodes, due to their ability to adapt to topology changes. However, with increasing number of nodes and increasing mobility of the nodes, maintaining sufficiently recent routing information becomes increasingly challenging. Existing routing protocols fail to operate reliably in case of sudden link or node failures.In this work, we propose a new routing approach called SourceShift to resiliently handle dynamic networks in the absence of current network status information. SourceShift uses opportunistic routing and network coding, like MORE, but also makes use of link local feedback, like ExOR. We evaluate SourceShift in random network topologies with link and node failures and compare the results with the state of the art. The evaluation shows that SourceShift can ensure the delivery of the message when feasible. Additionally, the use of local feedback can improve the airtime efficiency compared to other routing protocols, even in cases without link or node failures. As a result, SourceShift requires less than half the airtime of state of the art routing protocols in more than 60% of the evaluated cases.
{"title":"SourceShift: Resilient Routing in Highly Dynamic Wireless Mesh Networks","authors":"Andreas Ingo Grohmann, Frank Gabriel, Sandra Zimmermann, F. Fitzek","doi":"10.1109/WCNC45663.2020.9120818","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120818","url":null,"abstract":"Wireless networks have to support an increasing number of devices with increasing demands on mobility and resilience. Mesh network routing protocols provide an elegant solution to the problem of connecting mobile nodes, due to their ability to adapt to topology changes. However, with increasing number of nodes and increasing mobility of the nodes, maintaining sufficiently recent routing information becomes increasingly challenging. Existing routing protocols fail to operate reliably in case of sudden link or node failures.In this work, we propose a new routing approach called SourceShift to resiliently handle dynamic networks in the absence of current network status information. SourceShift uses opportunistic routing and network coding, like MORE, but also makes use of link local feedback, like ExOR. We evaluate SourceShift in random network topologies with link and node failures and compare the results with the state of the art. The evaluation shows that SourceShift can ensure the delivery of the message when feasible. Additionally, the use of local feedback can improve the airtime efficiency compared to other routing protocols, even in cases without link or node failures. As a result, SourceShift requires less than half the airtime of state of the art routing protocols in more than 60% of the evaluated cases.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126820396","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120612
Lei Gao, Yanzhao Hou, Xiaofeng Tao, Min Zhu
In recent years, vehicle-to-vehicle (V2V) communication underlaying cellular networks has attracted more and more attention both in academy and industry. In this paper, guaranteeing the latency and reliability of vehicle users (VUEs), we study the resource management problem to maximize the energy efficiency of VUEs while considering the QoS requirement of cellular users (CUEs). Based on the Lyapunov optimization theory, a novel two-layer power control and resource allocation scheme is proposed by exploiting the properties of fractional programming. Simulation results show that the proposed scheme can achieves remarkable improvements in terms of EE and ensure the latency and reliability requirements of V2V communication.
{"title":"Energy-Efficient Power Control and Resource Allocation for V2V Communication","authors":"Lei Gao, Yanzhao Hou, Xiaofeng Tao, Min Zhu","doi":"10.1109/WCNC45663.2020.9120612","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120612","url":null,"abstract":"In recent years, vehicle-to-vehicle (V2V) communication underlaying cellular networks has attracted more and more attention both in academy and industry. In this paper, guaranteeing the latency and reliability of vehicle users (VUEs), we study the resource management problem to maximize the energy efficiency of VUEs while considering the QoS requirement of cellular users (CUEs). Based on the Lyapunov optimization theory, a novel two-layer power control and resource allocation scheme is proposed by exploiting the properties of fractional programming. Simulation results show that the proposed scheme can achieves remarkable improvements in terms of EE and ensure the latency and reliability requirements of V2V communication.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126908611","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120633
Yoonseong Kang, Hyowoon Seo, Wan Choi
This paper studies a receive beamwidth controlling method in vehicle-to-infrastructure (V2I) wireless communication system using millimeter wave (mm-wave) band. We use a triangular beam pattern to model and characterize a mm-wave receive beam pattern. First of all, channel coherence time for line-of-sight (LoS) downlink transmission is derived under the given vehicular scenario. Then, we derive an attainable data rate for the time varying vehicular channel, by supposing that the beam is realigned whenever the channel coherence time is elapsed. In addition, the optimal receive beamwidth, which achieves the maximum point of the derived attainable data rate, is obtained. The effectiveness and feasibility of the proposed receive beamwidth controlling method is underpinned by both analytic and numerical simulation results. The results are also compared with a uniform linear array (ULA) beam pattern model and show that the triangular beam pattern model can well characterize the practical antenna model.
{"title":"Optimal Receive Beamwidth for Time Varying Vehicular Channels","authors":"Yoonseong Kang, Hyowoon Seo, Wan Choi","doi":"10.1109/WCNC45663.2020.9120633","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120633","url":null,"abstract":"This paper studies a receive beamwidth controlling method in vehicle-to-infrastructure (V2I) wireless communication system using millimeter wave (mm-wave) band. We use a triangular beam pattern to model and characterize a mm-wave receive beam pattern. First of all, channel coherence time for line-of-sight (LoS) downlink transmission is derived under the given vehicular scenario. Then, we derive an attainable data rate for the time varying vehicular channel, by supposing that the beam is realigned whenever the channel coherence time is elapsed. In addition, the optimal receive beamwidth, which achieves the maximum point of the derived attainable data rate, is obtained. The effectiveness and feasibility of the proposed receive beamwidth controlling method is underpinned by both analytic and numerical simulation results. The results are also compared with a uniform linear array (ULA) beam pattern model and show that the triangular beam pattern model can well characterize the practical antenna model.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115569933","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 : 2020-05-01DOI: 10.1109/WCNC45663.2020.9120634
Justin Kong, F. Dagefu, Brian M. Sadler
In this paper, we investigate a wireless network where multiple distributed transmitters adjust the phases of their signals so that they can be constructively added at an intended receiver (client). Unlike conventional beamforming with co-located and phase-synchronized antennas, geographically separated transmitters may have phase offsets induced by individual local carrier oscillators, that pose a challenge for coherent distributed beamforming. This is especially true for transmitters that are far apart, when distributed clock synchronization protocols may be more difficult to implement. There may also be a desired spatial repulsion among the positions of the transmitters in order to mitigate mutual coupling effects and extend the coverage region. In this regard, we analyze the performance of distributed beamforming with phase offsets by modeling the spatial distribution of the transmitters as a $beta$-Ginibre point process that models the repulsive behavior. We consider two transmission strategies: (i) Transmitter selection in which the client chooses the transmitter providing the highest received power at the client, and (ii) Coherent beamforming in which multiple transmitters simultaneously send their signals to the client. From numerical simulations, we examine the impact of the phase offsets on the performance and confirm the accuracy of our analysis. It is shown that even with significant phase offset errors, employing coherent beamforming can be an effective strategy.
{"title":"Performance Analysis of Distributed Beamforming With Random Phase Offsets","authors":"Justin Kong, F. Dagefu, Brian M. Sadler","doi":"10.1109/WCNC45663.2020.9120634","DOIUrl":"https://doi.org/10.1109/WCNC45663.2020.9120634","url":null,"abstract":"In this paper, we investigate a wireless network where multiple distributed transmitters adjust the phases of their signals so that they can be constructively added at an intended receiver (client). Unlike conventional beamforming with co-located and phase-synchronized antennas, geographically separated transmitters may have phase offsets induced by individual local carrier oscillators, that pose a challenge for coherent distributed beamforming. This is especially true for transmitters that are far apart, when distributed clock synchronization protocols may be more difficult to implement. There may also be a desired spatial repulsion among the positions of the transmitters in order to mitigate mutual coupling effects and extend the coverage region. In this regard, we analyze the performance of distributed beamforming with phase offsets by modeling the spatial distribution of the transmitters as a $beta$-Ginibre point process that models the repulsive behavior. We consider two transmission strategies: (i) Transmitter selection in which the client chooses the transmitter providing the highest received power at the client, and (ii) Coherent beamforming in which multiple transmitters simultaneously send their signals to the client. From numerical simulations, we examine the impact of the phase offsets on the performance and confirm the accuracy of our analysis. It is shown that even with significant phase offset errors, employing coherent beamforming can be an effective strategy.","PeriodicalId":415064,"journal":{"name":"2020 IEEE Wireless Communications and Networking Conference (WCNC)","volume":"188 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122365907","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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