This paper proposes an energy and spectrum efficient IoT network for 5G systems where spectrum is shared with the cellular system for spectrum efficiency and energy harvesting and energy transfer are utilized for energy efficiency. The IoT network, which consists of sensor nodes and a cluster head with a reliable energy source, reuses part of the cellular band whenever the cellular network does not utilize it. The cluster head performs spectrum sensing, random scheduling of the sensor nodes, and schedules some idle time for energy transfer. The sensor nodes harvest RF energy from the cellular traffic and the transferred energy from the cluster head. Provided the sensor nodes have sufficient energy, they transmit collected sensory data when scheduled. The inter-play between the cellular and IoT network introduces trade-offs between the spectrum availability, energy availability, information, and energy transfer. This paper shows that for the same cellular traffic level, as the number of sensor nodes in the network increases, the IoT network utilization increases resulting in a multi-user gain thanks to the broadcast nature of the energy transfer. The results offer insights into different operational regimes and exposes what type of IoT applications may be feasible with such networks.

Many of the video streaming applications in today's Internet involve the distribution of content from a CDN source to a large population of interested clients. However, widespread support of IP multicast is unavailable due to technical and economical reasons, leaving the floor to application layer multicast which introduces excessive delays for the clients and increased traffic load for the network. This paper is concerned with the introduction of an SDN-based framework that allows the network controller to not only deploy IP multicast between a source and subscribers, but also control, via a simple northbound interface, the distributed set of sources where multiple-description coded (MDC) video content is available. We observe that for medium to heavy network loads, relative to the state-of-the-art, the SDN-based streaming multicast video framework increases the PSNR of the received video significantly, from a level that is practically unwatchable to one that has good quality.

It is envisioned that access networks will be mostly wireless in the future. Hence, it is of interest to consider extensions of the Datagram Congestion Control Protocol (DCCP) for wireless networks. This paper focuses on the problems of video streaming over DCCP in the wireless domain and proposes a cross-layer solution in which the wireless packet loss information available in the Medium Access (MAC) layer is utilized by DCCP to distinguish congestion losses from wireless losses and behave accordingly. Tests performed with our modified DCCP confirm that using cross-layer loss information prevents unnecessary rate decreases and results in better video streaming experiences.

We consider peer-to-peer video broadcasting using cooperation among peers in an ad hoc wireless network. As opposed to the traditional single hop broadcasting, multiple hops cause an increase in broadcast video quality while creating interference and increasing transmission delay. We develop heuristics for the NP-complete problem of finding the subset of cooperating peers and the number of hops to maximize the data rate and to minimize the maximum observed delay in the system. Simulations show that using the proposed heuristics, different video sequences can be viewed at high qualities with acceptable delay among all peers.

In this paper, we consider a MIMO wireless relay network where communication between a source and a destination node is assisted by multiple relay nodes using the amplify-and-forward (AF) strategy. We consider a system where the source node multiplexes the information into parallel streams and uses disjoint subsets of relays to assist the transmission of each stream. Furthermore, we assume that the source and the destination have the same number of antennas and that each transmit antenna is virtually paired to a different destination antenna. We consider source node channel side information (CSI) availability of just the source-relay and source-destination links, and propose a source beamforming method based on maximizing the sum of signal-to-leakage ratios (SSLR) for all of the data streams. This method maximizes the sum of signal strengths at the set of relay nodes assigned to that stream while suppressing the interference to other relay nodes. Maximizing the SSLR reduces the propagation of interference terms in the AF strategy and results in significant performance gains.

Wireless video broadcasting is a complicated problem in which the number of users receiving the service and the average received video quality have to be intelligently optimized. In this paper, we propose a novel, multiple objective optimized cross-layer H.264/AVC video broadcasting scheme for a wireless system that supports a variety of transmission data-rates. The optimal compromise operating point, which includes H.264/AVC and physical layer parameters, between the maximization of the average received video PSNR and the minimization of the service outage probability is found using the multi-objective, cross- layer optimization. Simulations done for the ITU Pedestrian A and Vehicular B channels show that high-data rates with low outages are possible for video broadcasting using a cross-layer design.

Decentralized and dynamic behavior of peer to peer networks along with drawbacks of wireless environment necessitates the development of techniques achieving high reception rates and thus short reception times for the requestor peers. In this paper we discuss, through capacity optimization, the effects of user cooperation on the performance of a generalized wireless peer-to-peer network with additive white Gaussian noise (AWGN) channels. At the transmitter side, we utilize either parallel downloading, where transmitters send independent file portions, or user cooperation diversity, where transmitters simultaneously send same portions of the file. At the receiver side, we first analyze no cooperation case and then consider two cooperation strategies; decode-and-forward (DF) and amplify-and-forward (AF). We compare the performances of these transmitter and receiver cooperation schemes based on the time elapsed for the worst receiver to receive the whole file. Results show that user cooperation dramatically decreases reception times of the requestor peers.

In this paper we investigate multi-hop fading relay channels where the source, the destination and the multiple relay nodes are all equipped with multiple antennas. We study the ergodic capacities of multiple relay networks based on Amplify-and-Forward (AF) and Decode-and-Forward (DF) relaying modes. We examine multi-user beamforming (MU-BF), where each data stream is assumed to be matched to a specified relay node, based on the conventional eigen-mode transmission for both modes, and derive ergodic capacity expressions. We also examine the impact of the number of selected relay nodes on the network capacity both for modes of relaying. We show that by using MU-BF at the source node and a maximum number of relay nodes selected for cooperation, the network gains from multiplexing, while beyond that number of cooperating relay nodes, it only gains from relay selection.

We present a cross-layer optimized video rate adaptation and user scheduling scheme for multi-user wireless video streaming aiming for maximum quality of service (QoS) for each user,, maximum system video throughput, and QoS fairness among users. These objectives are jointly optimized using a multi-objective optimization (MOO) framework that aims to serve the user with the least remaining playback time, highest delivered video seconds per transmission slot and maximum video quality. Experiments with the IS-856 (1timesEV-DO) standard numerology and ITU pedestrian A and vehicular B environments show significant improvements over the state-of- the-art wireless schedulers in terms of user QoS, QoS fairness, and the system throughput.

In cellular environments video broadcasting is a challenging problem in which the number of users receiving the service and the average QoS has to be intelligently optimized. For video broadcasting in a 1xEV-DO system, the orthogonal Walsh codes may be distributed among the multiple layers of the scalable coded video stream. In this paper, we propose a novel, multiple objective optimized, multi-layered video broadcasting scheme for the 1xEV-DO system. With this scheme, the average observed service quality is maximized while minimizing the total number of time slots in which individual mobile subscribers experience outages. Simulations done for the ITU Pedestrian A and Vehicular B channels show that our proposed scenario provide significant increase to the average service quality while maintaining the total number of slots receiving no service as small as in original scenario.

In wireless networks, transmission of constant-quality, high bitrate video is a challenging task due to channel capacity and buffer limitations. Content adaptive rate control, is used as a solution to this problem. Instead of transmitting all of the video content at low quality, the most important content can be transmitted at high quality while still preserving an acceptable quality for the remaining segments. Furthermore, the rate control strategy inside the individual temporal segments plays a key role for the network performance and viewing quality. Although constant quality video encoding inside the temporal segments is preferable for the best viewing experience, it causes more network packet losses due to adverse bitrate fluctuations in the video stream. In cases when the network is too much loaded, it may be better to employ constant bitrate encoding for network friendliness. In this paper, a performance analysis of constant bitrate and constant peak signal-to-noise ratio encoding for content adaptive rate controlled video streaming over wireless networks is presented. Experimental results obtained using AVC/H.264 encoding in a CDMA/HDR multi-user environment with cross-layer optimized scheduling show performance comparisons of CBR and CPSNR encoding.

In mobile video transmission systems, the initial delay for pre-fetching video at the client buffer needs to be short due to buffer limitations and application-layer user convenience. Therefore, an effective cross-layer wireless design is required that considers both physical and application layer aspects of such a system. We present a cross-layer optimized multi-user video adaptation and scheduling scheme for wireless video communication, where quality-of-service (QoS) fairness among users is provided while maximizing user convenience and video throughput. Application and physical layer aspects are jointly optimized using a multi-objective optimization (MOO) framework that tries to schedule the user with the least remaining playback time and the highest video throughput (delivered video seconds per transmission slot) with maximum video quality. Experiments with the IS-856 (1xEV-DO) standard and ITU pedestrian A and vehicular B environments show the improvements over today's schedulers in terms of QoS fairness and user utility.

In wireless packet transmission systems, it is crucial to provide fairness in service while maximizing user utility and channel throughput. This is possible via intelligent allocation of system resources. For real time video applications, a pre-roll time for pre-fetching data at the client buffer is needed in order to compensate for channel variations that cause client buffer under/overflows, hence facilitating continuous playout of the video. In this paper, a novel multiple objective optimized (MOO) opportunistic multiple access scheme for optimal scheduling of users in a 1xEV-DO (IS-856) system is presented. At each time slot, the user that experiences the best compromise between the least buffer occupancy and the best channel condition is served. Experiments conducted in ITU Pedestrian A and Vehicular B environments show that our algorithm treats each user fairly while its channel throughput performance is very close to the ideal case, in which the user with the best channel characteristics is always served with no buffer constraints.

We present new scheduling algorithms for the HDR wireless packet data system to provide superior statistical QoS guarantees. Here, instead of QoS assurances we guarantee the percentage of time the QoS requirements are satisfied and develop new scheduling algorithms accordingly. We compare these schedulers with the maximum rate, proportional fair and exponential rules from the literature. We observe that the statistical QoS guarantee is an attractive alternative to the assured QoS for the wireless platform since such strict QoS assurances decrease the wireless system performance significantly.

This work presents a feasibility study for a possible extension to the IS-856 (HDR, 1xEV-DO) standard in terms of allowing two user transmission in the system downlink. Since the 1.25 MHz bandwidth of this system is not perfectly frequency flat, the one user at a time scheme is no longer optimal in theory. Furthermore, the two user transmission allows for more granular data rate selection by the base station. The extension requires minimum changes to the physical layer of the IS-856 standard and is compatible with the existing physical layer specifications with no additional overhead required in the downlink. A packet scheduling algorithm that is able to take advantage of the two user transmission is presented. The performance of the proposal is studied with physical layer and system simulations. The simulation results indicate that the proposed extension modestly increases the average system data rate that may not justify the required complexity.

The performance characteristics of a multicode CDMA downlink with systematic convolutional (turbo) coding are obtained under a shadowed multipath fading mobile channel. Two different iterative decoding methods are compared in two different synchronous downlink schemes operating under given channel conditions with the same transmission bandwidth as in IS-95. Multicode CDMA with logMAP decoding is observed to provide better QoS with lower bit and frame error rates, reasonable complexity and shorter decoding delay compared to DS-CDMA downlink with single code pair assigned to each user.

The different QoS and data rate requirements of communication channels can be satisfied by varying one or more of the coding, digital modulation and spreading blocks. Keeping the transmission bandwidth fixed as in IS-95, four different interblock data rate configurations are compared. User powers are kept constant in the performance simulations. Various coding, modulation and spreading rate combinations yield different performance characteristics in AWGN, flat fading and multipath environments permitting trade-off decisions on choices of rate, QoS, and implementation.

Provision of a large variety of services is expected in the upcoming third generation wireless systems. Users with very different and even time varying rate and quality of service (QoS) requirements will need to be accommodated. In order to provide such diversity, the network has to be able to statistically multiplex different rate and QoS users together while maximizing the spectral efficiency. In a given fixed channel bandwidth, there are two basic methods with which variable rate services may be implemented in the forward link physical layer of a DS CDMA system: allocating each user one code channel that has a variable spreading factor or allocating multiple codes to each user so that the individual user data streams are split into parallel lower rate streams which in turn are each spread by different, higher order orthogonal codes. Clearly, hybrids of the two methods are feasible as well. This paper is concerned with investigating the effects of these configurations on the overall system performance. Impact on both uniform and hybrid traffic is considered for a multitude of channel models.

A simulation bed to investigate the feasibility of a CDMA based indoor residential system underlay that uses time division duplexing and dynamic channel allocation is described. The indoor system in question shares the same frequency band as the outdoor ANSI-008 based cellular PCS network and operates within its coverage area. Due to the TDD nature of the residential system, both the forward and reverse link signals are transmitted in the same frequency band in different time slots. Dynamic channel allocation (DCA) is used to select either the PCS uplink or the PCS downlink frequency band for the indoor system operation. The developed simulation bed measures the effects of the indoor system to the outdoor system and vice versa. System capacities, outages, DCA usage rates and blockage rates are measured using the simulator. The simulation results show that underlaying such an indoor residential system to the existing ANSI-008 PCS system is feasible. In a given geographical area, addition of such a system would ultimately increase the CDMA capacity substantially.

Efficient series that are used to calculate the bit error probabilities for biphase spread and quadriphase spread, BPSK modulated, asynchronous DS CDMA systems are derived. These series are then used to investigate the degradation in the performance of both systems due to synchronization errors. The analysis requires the characteristic functions of the multiple access interference and of the self interference and these functions have been expressed in terms of the special functions of mathematical physics. It is found that both systems have comparable performance when synchronization errors are considered. Thus, as far as the system capacity is concerned, quadriphase spreading does not offer any advantage relative to the simpler biphase spread system.