60 GHz MAC Standardization: Progress and Way Forward

Communication at mmWave frequencies has been the focus in the recent years. In this paper, we discuss standardization efforts in 60 GHz short range communication and the progress therein. We compare the available standards in terms of network architecture, medium access control mechanisms, physical layer techniques and several other features. Comparative analysis indicates that IEEE 802.11ad is likely to lead the short-range indoor communication at 60 GHz. We bring to the fore resolved and unresolved issues pertaining to robust WLAN connectivity at 60 GHz. Further, we discuss the role of mmWave bands in 5G communication scenarios and highlight the further efforts required in terms of research and standardization

Design and analysis of LTE-WLAN wireless router with QOS preservation

Future wireless networks are envisioned to embrace a higher level of heterogeneity whereby different wireless technologies such as Long Term Evolution UMTS (LTE), Wireless Local Area Network (WLAN), WCDMA/HSPA, WiMAX, etc, not only will coexist but will also cooperate more closely. This is motivated by the fact that several complementary characteristics exist between these technologies. For example, one technology can be used as access technology while the other can be used for backhaul. To interconnect two or more wireless technologies, the usage of routing device is inevitable. In order to preserve the Quality of Service (QoS) across these technologies which come with different QoS definitions, a more comprehensive approach is required to preserve QoS across two diverse wireless technologies i.e. Enhanced Distributed Coordination Function (EDCA) for WLAN and Uplink/Downlink packet scheduling for LTE. WLAN is reasonably priced, easy to deploy and has been enjoying a wide market acceptance especially in the indoor. The LTE is expected to be the dominant 4G cellular technology. However it will take some time before LTE can attain the same level of adoption as what WLAN has achieved especially in the consumer market. The main objective of this research project is to design an access router that enables the interworking between WLAN and LTE with QoS preservation. First, the performance of both WLAN and LTE radio interfaces are investigated independently in terms of the data rates, user/system throughput, effect of multiple access and spectral efficiency. Next, different approaches and schemes which facilitate QoS preservation between WLAN and LTE over the router are investigated and evaluated in terms of different performance metrics (voice Mean Opinion Score, video delay, video traffic received, video jitter, video packet loss rate). The design and analysis of the performance are carried out through simulation as the only feasible approach to accomplish this work. OPNET Modeler is used to model the LTE-WLAN router as well as to perform the analysis. The results of this research verify the feasibility of the proposed router architecture and the interworking paradigm. The elegance of the proposed router implementation is that it does not require massive change in the existing wireless systems, LTE and WLAN to preserve the QoS. The results of the performance analysis show that it is crucial to have a QoS preservation mechanism in the router IP layer at any potential congestion point in the wireless network, to ensure that delay-sensitive and loss-sensitive applications, such as real-time video and voice, pass through unimpeded, relative to the loss-tolerant and delay-tolerant data applications. The comparison of the designed IP QoS preservation scheme namely, Priority Queuing without Block Acknowledgement (PQ noBA) shows that it can support 50% more multimedia application across the router than the other scheme

CogCell: Cognitive Interplay between 60GHz Picocells and 2.4/5GHz Hotspots in the 5G Era

Rapid proliferation of wireless communication devices and the emergence of a variety of new applications have triggered investigations into next-generation mobile broadband systems, i.e., 5G. Legacy 2G--4G systems covering large areas were envisioned to serve both indoor and outdoor environments. However, in the 5G-era, 80\% of overall traffic is expected to be generated in indoors. Hence, the current approach of macro-cell mobile network, where there is no differentiation between indoors and outdoors, needs to be reconsidered. We envision 60\,GHz mmWave picocell architecture to support high-speed indoor and hotspot communications. We envisage the 5G indoor network as a combination of-, and interplay between, 2.4/5\,GHz having robust coverage and 60\,GHz links offering high datarate. This requires an intelligent coordination and cooperation. We propose 60\,GHz picocellular network architecture, called CogCell, leveraging the ubiquitous WiFi. We propose to use 60\,GHz for the data plane and 2.4/5GHz for the control plane. The hybrid network architecture considers an opportunistic fall-back to 2.4/5\,GHz in case of poor connectivity in the 60\,GHz domain. Further, to avoid the frequent re-beamforming in 60\,GHz directional links due to mobility, we propose a cognitive module -- a sensor-assisted intelligent beam switching procedure -- which reduces the communication overhead. We believe that the CogCell concept will help future indoor communications and possibly outdoor hotspots, where mobile stations and access points collaborate with each other to improve the user experience.Comment: 14 PAGES in IEEE Communications Magazine, Special issue on Emerging Applications, Services and Engineering for Cognitive Cellular Systems (EASE4CCS), July 201

Evaluations and Enhancements in 802.11n WLANs – Error-Sensitive Adaptive Frame Aggregation

IEEE 802.11n is a developing next-generation standard for wireless local area network (LAN). Seamless multimedia traffic connection will become possible with the 802.11n improvement in the Physical and MAC layer. The new 802.11n frame aggregation technique is particularly important for enhancing MAC layer efficiency under high speed wireless LAN. Although the frame aggregation can increase the efficiency in the MAC layer, it does not provide good performance in high BER channels when using large frame aggregation size. An Optimal Frame Aggregation (OFA) technique for AMSDU frame under different BERs in 802.11n WLANs was proposed. However, the suggested algorithm does not take into account the loss rate and the delay performance requirements for Voice or Video multimedia traffic in various BER channels. The optimal frame size can provide good throughput in the network, but the delay might exceed the Quality of Service (QoS) requirement of Voice traffic or the Frame-Error-Rate (FER) might exceed the maximum loss rate tolerable by the streaming Video traffic. We propose an Error- Sensitive Adaptive Frame Aggregation (ESAFA) scheme which can dynamically set the size of AMSDU frame based on the maximum Frame-Error-Rate (FER) tolerable by a particular multimedia traffic. The simulations show that our adaptive algorithm outperforms the optimal frame algorithm by improving both the delay and the loss rate in the 802.11n WLANs. The measured FER of the Error-Sensitive Adaptive Frame Aggregation scheme can be kept at about the same as the loss rate requirement for Video traffic even under high Bit-Error-Rate (BER) channel. The delay compared to OFA is also decreased by around 50% under different channel conditions. Moreover, the results show that the Error-Sensitive Adaptive Frame Aggregation scheme works particularly well in error-prone wireless networks

Experimental Performance Evaluation and Frame Aggregation Enhancement in IEEE 802.11n WLANs

The IEEE 802.11n standard promises to extend today’s most popular WLAN standard by significantly increasing reach, reliability, and throughput. Ratified on September 2009, this standard defines many new physical and medium access control (MAC) layer enhancements. These enhancements aim to provide a data transmission rate of up to 600 Mbps. Since June 2007, 802.11n products are available on the enterprise market based on the draft 2.0. In this paper we investigate the effect of most of the proposed 802.11n MAC and physical layer features on the adhoc networks performance. We have performed several experiments in real conditions. The experimental results demonstrated the effectiveness of 802.11n enhancement. We have also examined the interoperability and fairness of 802.11n. The frame aggregation mechanism of 802.11n MAC layer can improve the efficiency of channel utilization by reducing the protocol overheads. We focused on the effect of frame aggregation on the support of voice and video applications in wireless networks. We also propose a new frame aggregation scheduler that considers specific QoS requirements for multimedia applications. We dynamically adjust the aggregated frame size based on frame's access category defined in 802.11e standard