The new IEEE 802.11 standard, IEEE 802.11ax, has the challenging goal of serving more Uplink (UL) traffic and users as compared with his predecessor IEEE 802.11ac, enabling consistent and reliable streams of data (ave...The new IEEE 802.11 standard, IEEE 802.11ax, has the challenging goal of serving more Uplink (UL) traffic and users as compared with his predecessor IEEE 802.11ac, enabling consistent and reliable streams of data (average throughput) per station. In this paper we explore several new IEEE 802.11ax UL scheduling mechanisms and compare between the maximum throughputs of unidirectional UDP Multi Users (MU) triadic. The evaluation is conducted based on Multiple-Input-Multiple-Output (MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) transmission multiplexing format in IEEE 802.11ax vs. the CSMA/CA MAC in IEEE 802.11ac in the Single User (SU) and MU modes for 1, 4, 8, 16, 32 and 64 stations scenario in reliable and unreliable channels. The comparison is conducted as a function of the Modulation and Coding Schemes (MCS) in use. In IEEE 802.11ax we consider two new flavors of acknowledgment operation settings, where the maximum acknowledgment windows are 64 or 256 respectively. In SU scenario the throughputs of IEEE 802.11ax are larger than those of IEEE 802.11ac by 64% and 85% in reliable and unreliable channels respectively. In MU-MIMO scenario the throughputs of IEEE 802.11ax are larger than those of IEEE 802.11ac by 263% and 270% in reliable and unreliable channels respectively. Also, as the number of stations increases, the advantage of IEEE 802.11ax in terms of the access delay also increases.展开更多
With the ever-increasing range of video and audio applications in portable handheld devices, demand for high throughput in Wi-Fi networks is escalating. In this paper we introduce several novel features defined in nex...With the ever-increasing range of video and audio applications in portable handheld devices, demand for high throughput in Wi-Fi networks is escalating. In this paper we introduce several novel features defined in next generation WLAN, termed as IEEE 802.11ax standard, and compare between the maximum throughputs received in IEEE 802.11ax and IEEE 802.11ac in a scenario where the AP continuously transmits to one station in the Single User mode. The comparison is done as a function of the modulation/coding schemes in use. In IEEE 802.11ax we consider two levels of frame aggregation. IEEE 802.11ax outperforms IEEE 802.11ac by about 29% and 48% in reliable and unreliable channels respectively.展开更多
Our paper presents an interactive four-dimensional model for studying the long- and short-term development of the communication discipline with Israel serving as a case study： institutional-contextual, institutional-...Our paper presents an interactive four-dimensional model for studying the long- and short-term development of the communication discipline with Israel serving as a case study： institutional-contextual, institutional-in-field, intellectual-contextual, and intellectual-in-field. Our empirical analysis utilized personal interviews, archive documents, and statistical data. Four main processes were discerned： transition from integration to alienation between institutions of higher learning and the larger political and ideological context; a shift from Hebrew University Institute of Communication＇s institutional monopoly to a multiplicity of increasingly competitive communication schools/departments; transition from intellectual hegemony to limited intellectual diversity; and gradually improving status for the communication field among social science disciplines. Our case-study analysis validated the interactive relationship among the model＇s conceptual dimensions, calling for future cross-national comparisons.展开更多
The new IEEE 802.11ax standard is aimed to serve many users while enabling every station to transmit a consistent stream of data without interruption. In this paper we evaluate the upper bound on the throughput of a D...The new IEEE 802.11ax standard is aimed to serve many users while enabling every station to transmit a consistent stream of data without interruption. In this paper we evaluate the upper bound on the throughput of a Downlink IEEE 802.11ax channel using the Single User (SU) mode and using the Multi User Multiple-Input-Multiple-Output (MU-MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) mode. We compare between IEEE 802.11ax and IEEE 802.11ac for the case of 1, 4, 8, 16, 32 and 64 stations in different Modulation/Coding schemes (MCS) and different transmission windows’ sizes, 64 and 256 frames in IEEE 802.11ax. IEEE 802.11ax outperforms IEEE 802.11ac in the SU and MU modes by 52% and 74% in a reliable channel respectively, while in an unreliable channel the improvements are by 59% and 103% respectively. Also, in terms of the access delay, the advantage of IEEE 802.11ax increases as the number of stations increases.展开更多
This paper suggests a new model for the transmission of Transmission Control Protocol (TCP) traffic over IEEE 802.11 using the new features of IEEE 802.11ac. The paper examines the first step in this direction and as ...This paper suggests a new model for the transmission of Transmission Control Protocol (TCP) traffic over IEEE 802.11 using the new features of IEEE 802.11ac. The paper examines the first step in this direction and as such we first consider a single TCP connection, which is typical in a home environment. We show that when the IEEE 802.11ac MAC is aware of QoS TCP traffic, using Reverse Direction improves the TCP Goodput in tens of percentages compared to the traditional contention based channel access. In an error-free channel this improvement is 20% while in an error-prone channel the improvement reaches 60% also using blind retransmission of frames. In our operation modes we also assume the use in Two-Level aggregation scheme, the Automatic Repeat-Request (ARQ) protocol of the IEEE 802.11ac MAC layer, the data rates and the four Access Categories defined in this standard.展开更多
In this paper we suggest a novel idea to improve the Throughput of a rapidly changing WiFi channel by exploiting the standard aggregation schemes in IEEE 802.11ac networks. The idea is based on blindly transmitting se...In this paper we suggest a novel idea to improve the Throughput of a rapidly changing WiFi channel by exploiting the standard aggregation schemes in IEEE 802.11ac networks. The idea is based on blindly transmitting several copies of the first 4 MAC Protocol Data Units (MPDU) in the Transmission Window. This increases the probability that the window moves forward, enabling the transmission of new MPDUs and resulting in increased Throughput. It turns out that transmitting 2 copies of each of the first 4 MPDUs yields the best Throughput gain, in the order of 50% - 60% in PHY rates of 1.3 - 3.5 Gbps and few hundreds of bytes MPDUs. The proposed idea has advantage over Link Adaptation since it reduces the actual PHY rate only for the transmission of few MPDUs while Link Adaptation reduces the PHY rate for all the transmissions.展开更多
文摘The new IEEE 802.11 standard, IEEE 802.11ax, has the challenging goal of serving more Uplink (UL) traffic and users as compared with his predecessor IEEE 802.11ac, enabling consistent and reliable streams of data (average throughput) per station. In this paper we explore several new IEEE 802.11ax UL scheduling mechanisms and compare between the maximum throughputs of unidirectional UDP Multi Users (MU) triadic. The evaluation is conducted based on Multiple-Input-Multiple-Output (MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) transmission multiplexing format in IEEE 802.11ax vs. the CSMA/CA MAC in IEEE 802.11ac in the Single User (SU) and MU modes for 1, 4, 8, 16, 32 and 64 stations scenario in reliable and unreliable channels. The comparison is conducted as a function of the Modulation and Coding Schemes (MCS) in use. In IEEE 802.11ax we consider two new flavors of acknowledgment operation settings, where the maximum acknowledgment windows are 64 or 256 respectively. In SU scenario the throughputs of IEEE 802.11ax are larger than those of IEEE 802.11ac by 64% and 85% in reliable and unreliable channels respectively. In MU-MIMO scenario the throughputs of IEEE 802.11ax are larger than those of IEEE 802.11ac by 263% and 270% in reliable and unreliable channels respectively. Also, as the number of stations increases, the advantage of IEEE 802.11ax in terms of the access delay also increases.
文摘With the ever-increasing range of video and audio applications in portable handheld devices, demand for high throughput in Wi-Fi networks is escalating. In this paper we introduce several novel features defined in next generation WLAN, termed as IEEE 802.11ax standard, and compare between the maximum throughputs received in IEEE 802.11ax and IEEE 802.11ac in a scenario where the AP continuously transmits to one station in the Single User mode. The comparison is done as a function of the modulation/coding schemes in use. In IEEE 802.11ax we consider two levels of frame aggregation. IEEE 802.11ax outperforms IEEE 802.11ac by about 29% and 48% in reliable and unreliable channels respectively.
文摘Our paper presents an interactive four-dimensional model for studying the long- and short-term development of the communication discipline with Israel serving as a case study： institutional-contextual, institutional-in-field, intellectual-contextual, and intellectual-in-field. Our empirical analysis utilized personal interviews, archive documents, and statistical data. Four main processes were discerned： transition from integration to alienation between institutions of higher learning and the larger political and ideological context; a shift from Hebrew University Institute of Communication＇s institutional monopoly to a multiplicity of increasingly competitive communication schools/departments; transition from intellectual hegemony to limited intellectual diversity; and gradually improving status for the communication field among social science disciplines. Our case-study analysis validated the interactive relationship among the model＇s conceptual dimensions, calling for future cross-national comparisons.
文摘The new IEEE 802.11ax standard is aimed to serve many users while enabling every station to transmit a consistent stream of data without interruption. In this paper we evaluate the upper bound on the throughput of a Downlink IEEE 802.11ax channel using the Single User (SU) mode and using the Multi User Multiple-Input-Multiple-Output (MU-MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) mode. We compare between IEEE 802.11ax and IEEE 802.11ac for the case of 1, 4, 8, 16, 32 and 64 stations in different Modulation/Coding schemes (MCS) and different transmission windows’ sizes, 64 and 256 frames in IEEE 802.11ax. IEEE 802.11ax outperforms IEEE 802.11ac in the SU and MU modes by 52% and 74% in a reliable channel respectively, while in an unreliable channel the improvements are by 59% and 103% respectively. Also, in terms of the access delay, the advantage of IEEE 802.11ax increases as the number of stations increases.
文摘This paper suggests a new model for the transmission of Transmission Control Protocol (TCP) traffic over IEEE 802.11 using the new features of IEEE 802.11ac. The paper examines the first step in this direction and as such we first consider a single TCP connection, which is typical in a home environment. We show that when the IEEE 802.11ac MAC is aware of QoS TCP traffic, using Reverse Direction improves the TCP Goodput in tens of percentages compared to the traditional contention based channel access. In an error-free channel this improvement is 20% while in an error-prone channel the improvement reaches 60% also using blind retransmission of frames. In our operation modes we also assume the use in Two-Level aggregation scheme, the Automatic Repeat-Request (ARQ) protocol of the IEEE 802.11ac MAC layer, the data rates and the four Access Categories defined in this standard.
文摘In this paper we suggest a novel idea to improve the Throughput of a rapidly changing WiFi channel by exploiting the standard aggregation schemes in IEEE 802.11ac networks. The idea is based on blindly transmitting several copies of the first 4 MAC Protocol Data Units (MPDU) in the Transmission Window. This increases the probability that the window moves forward, enabling the transmission of new MPDUs and resulting in increased Throughput. It turns out that transmitting 2 copies of each of the first 4 MPDUs yields the best Throughput gain, in the order of 50% - 60% in PHY rates of 1.3 - 3.5 Gbps and few hundreds of bytes MPDUs. The proposed idea has advantage over Link Adaptation since it reduces the actual PHY rate only for the transmission of few MPDUs while Link Adaptation reduces the PHY rate for all the transmissions.
