Dynamic spectrum sharing techniques for next generation networks

Wireless communication networking technology plays an important part in supporting ubiquitous network. IT, BT and NT convergence of typical techniques for wireless body area network (WBAN) provides the quality and convenience. WBAN is classified in to non-medical field and medical field. In this paper, the techniques, applications and channel models of WBAN are analyzed. WBAN technique is a based on IEEE 802.15.6 TG WBAN. The applications of WBAN are classified into healthcare, assisted living and entertainment.

The promise of future generations of mobile communication, both 5.5 and 6G, is that of continued increases in capacity and coverage of the wireless communication network together with novel applications demanding higher levels of performance between the mobile devices and their applications on servers in the cloud. In addition, the growing shift towards virtualization of network function itself offers perhaps the most stringent requirements on the network. To continue to offer ever higher capacities and speeds, future networks will be required to further densify addressing capacity and coverage demands through the use of small cells or new radio spectral bands, such as 7-20GHZ or sub-THZ, with inherently shorter range. Therein lies the dilemma. A denser and ever more complex network of access points, with higher speeds and performance, but continued pressure on the deployment and costs. To address this challenge solutions which address all aspects of the End to End network must be considered together – the mobile access points, transport networks, deployment options, and edge cloud all contribute equally to the success of the new consumer and industrial applications promised for next generation networks as well as the operation of the networks themselves. In this paper we will outline the expected requirements of next generation networks as well as new technologies and methods which address the simultaneous challenges of higher capacity, lower costs, and reliable deterministic performance.

Wireless body area networks (WBAN) emerge as one of the main research streams for future wireless communications. One of the candidates for the WBAN physical layer is multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) technology. However, despite its high data rate feature, it performs poorly in the very dispersive WBAN channel. To improve its performance, this paper proposes two novel mechanisms. First, the space-time-frequency coding (STFC) is introduced into MB-OFDM UWB system in order to enhance the diversity order, resulting in a substantial improvement in the average error performance compared to the conventional MB-OFDM UWB system. Nevertheless, the performance is very sensitive to the body orientation towards the transmitter due to the body shadowing effect. Secondly, to improve further the performance of the proposed STFC MB-OFDM UWB system in all body directions, we propose an adaptive scheme that changes the modulation, STFC coding rate, and constellation power. Simulations confirm that an additional improvement in the order of 1 to 3 dB is achieved by the adaptive system. This improvement practically means a possible 12.5% to 50% reduction of the power consumption, which may also result in smaller size of WBAN devices.

The combination of emerging new communication technologies, economic growth, and current limitations on the amount of available dedicated spectrum necessitate sharing spectrum dynamically between incumbent (primary) users and opportunistic (secondary) users. This paper builds upon the seminal “spectrum jails” paradigm — a mathematical model for light-handed ex-post enforcement. Analyzing this as a Stackelberg game, we examine what kinds of rights for primaries and secondaries we can credibly enforce. While the primary cannot possibly be made to trust that secondaries will always be honest, it can trust that it will be protected from too much harmful interference and we show how the enforcer can set the ex-post enforcement parameters to do this no matter which secondary user becomes capable of using the band. Similarly, it is impossible to give a universal guarantee to all secondary users that the primary will never make false reports (“cry wolf”) against them. However, it is possible to show that “compatible” secondary users will trust that the primary user will not make false reports against them when the spectrum opportunity is sufficiently attractive for them to use.

A cognitive radio-based spectrum allocation scheme using an active cooperative-aware mechanism is proposed in this paper. The scheme ensures that the primary user and secondary users cooperate actively for their own benefits. The primary user releases some spectrum resources to secondary users to actively stimulate them to actively join the cooperative transmission of the primary user, and secondary users help the primary user to relay data in return, as well as its self-data transmission at the same time. The Stackelberg game is used to evenly and jointly optimize the utilities of both the primary and secondary users. Simulation results show that the proposed active cooperation-aware mechanism could improve the body sensor network performance.

Dynamic spectrum access techniques utilized in cognitive radio systems allow more efficient use of spectrum. In such systems, secondary users are supposed to operate in primary users' spectrum without interfering them. In this paper, we investigate an opportunistic spectrum sharing technique in cognitive radio networks for a special case in which, two secondary users are allowed to coexist in a channel (sub-banding). The sub-banding process in the proposed algorithm is such that, when all the channels are occupied by the primary and secondary users, then the secondary users' channels can be divided into two subbands, and two secondary users may use a sub-band, simultaneously. For performance evaluation, we have derived metrics such as blocking probability, dropping probability, and channel utilization, and then, the simulation results for the cases of using and not using sub-banding for the secondary users have been compared. It is observed that in a spectrum sharing system, channel sub-banding significantly reduces the blocking and dropping probabilities of the secondary users, with the cost of lower quality channels compared to the state without using sub-bands.

To examine the practical potential of an optical body area network (BAN) technique, a feasibility study was conducted of optical data transmission through a human hand using diffusely scattered light. The data transmission of 170 mm distance in a human hand was accomplished to show the possibility of the data transmission from the wrist to the fingertips in an adult hand. The frequency bandwidth for data transmission was restricted by the effect of strong scattering inside body tissues. In experiments using a human hand, the bandwidth was measured to be 2.80 GHz. The feasibility of BAN using diffusely scattered light in the body was verified through these analyses.

The use of small cells is a promising way of providing the required capacity in future cellular networks through densification. Self-organizing network (SON) techniques are required in small cells, particularly in femtocells where plug-and-play user deployments are used. However, these techniques have tended to be implemented by vendors with proprietary algorithms that use low-level UE measurements which are not easily accessible to network operators. This makes the management of femtocells in a multi-vendor environment difficult. In this paper, we present a centralized SON technique to perform load balancing, coverage optimization and manage sleep modes that utilizes high-level measurements made at the femtocells which are easily available through the widely used TR-069 device management protocol standard. This allows network operators the flexibility of implementing and coordinating the SON techniques in multi-vendor femtocell deployments. We show that, despite the limited amount of information used, the proposed solution is able to effectively optimize the coverage in order to balance load and manage sleep modes whilst ensuring that no coverage gaps occur.

The future of healthcare delivery systems and tele medical applications will undergo a radical change due to the developments in wearable technologies, medical sensors, mobile computing and communication techniques. E-health was born with the integration of networks and telecommunications when dealing with applications of collecting, sorting and transferring medical data from distant locations for performing remote medical collaborations and diagnosis. Energy requirement is central to many battery-constrained systems, but they are essential in body sensor networks (BSNs) due to energy and resource constraints, and the critical nature of many healthcare applications. On-node signal processing and compression techniques can save energy by greatly reducing the amount of data transmitted over the wireless channel, but lossy techniques can incur a reduction in application. In this paper we are proposing an aggregation of Deflate and RLE algorithm called Aggregated Deflate RLE (ADR). ADR compression algorithm which provides better compression ratio with minimum compression time as compared to other existing compression techniques like LZW, Huffman and Deflate. We provide here various comparative result of our algorithm with above compression techniques which proves that we are providing best technique for compression of body sensor network data.

This paper proposes a novel spectrum sharing technique for an existing wireless local area network (LAN) system (primary user) based on IEEE 802.11a, and a new system (secondary user) equipped with the proposed spectrum sharing technique. Both systems are assumed to behave according to carrier sense multiple accesses with collision avoidance (CSMA/CA) protocol. An objective of spectrum sharing techniques is to achieve higher secondary user's throughput while the primary user's throughput is maintained. We utilize one key parameter, the channel occupancy rate (COR), which is the channel usage rate of the primary or secondary system. The proposed spectrum sharing technique is the minimum CW size selection (MCWSS) for secondary users to control the COR of secondary system. We set an alternative objective which is to maximize the COR for secondary system while COR of the primary system is maintained. By computer simulations, we show that by the MCWSS secondary user can maintain the constraint for the primary system and achieve the target COR performance and it leads to the higher secondary user's throughput performance, while maintaining the primary user's throughput performance.

Opportunistic availability of licensed frequency bands enables the secondary users (SUs) to avail the radio spectrum dynamically. Cognitive radio (CR) paradigm extends the dynamic spectrum access techniques to sense for free channels (called spectrum holes) which can be efficiently redistributed amongst SUs. Motivated by the adaptive technology in CR, this paper introduces a sealed-bid double auction mechanism which aims to obtain an effective allocation of the unused radio spectrum. The proposed auction model adopts multi-channel allocation where one SU can access more than one available channel, while imposing the constraints for dynamics in spectrum opportunities and varying channel availability time amongst SUs. Previously designed double auctions miss out the CR constraints which can further degrade the network performance. Also, multi-winner allocation is induced in the model which encourages spectrum reuse by allowing a common channel to be assigned to multiple non-interfering SUs. A preference list of channels is maintained at each SU using which SUs offer their bid values for the heterogeneous channels which the primary owners are competing to lease. To organize channel specific groups of non-interfering SUs, a bidder group formation algorithm is developed such that members of a winner group get access to a common channel. The auctioneer formulates a winner determination strategy and a pricing strategy which achieves truthfulness while assigning the idle spectrum. Effectiveness of the proposed model is studied by comparing it with an existing work which shows that channel allocation gets significantly improved on deploying the proposed model.

This paper aims to propose and analyze an energy-and spectrum-efficient wireless body area network (WBAN) for smart healthcare applications. On one hand, we focus on improving the spectrum utilization in WBANs by incorporating an overlay cognitive radio (CR) paradigm that allows the co-existence of various sensor nodes as primary and secondary users based on their applications i.e., medical or non-medical. On the other hand, we employ an energy harvesting (EH) based time-switching cooperation protocol through the secondary device to improve energy efficiency. We evaluate the performance of the proposed overlay CR WBAN in terms of outage probability, throughput and energy efficiency, and thereby provide practical design guidelines in IoT-based e-healthcare framework. Above all, we assess the correctness of the proposed analytical framework when compared to Monte Carlo simulations.

This paper investigates the optimal number of collaborating secondary users which can minimize the total error rate (i.e., the summation of probabilities of missed detection and false alarm) for cooperative spectrum sensing when the secondary users follow Poisson point process (PPP). The received signal-to-noise ratios (SNRs) at secondary users can vary since the practical locations and the amount of secondary users are various. In order to cope with the diversity of received SNRs, a practical cooperative spectrum sensing system model is proposed based on the generalized likelihood ratio test (GLRT) detector. Firstly, the analytical expressions of the probabilities of false alarm and detection are derived. Secondly, an efficient cooperative spectrum sensing technique is proposed, which only requires the least amount of cooperative secondary users to achieve the minimum total error rate. Furthermore, the analytical results reveal the chosen optimal numbers of collaborating secondary users can achieve the best spectrum sensing performance.

Green communications is an inevitable trend for future communication network design, especially for a cognitive radio network. Power allocation strategies are of crucial importance for green cognitive radio networks. However, energy-efficient power allocation strategies in green cognitive radio networks have not been fully studied. Energy efficiency maximization problems are analyzed in delay-insensitive cognitive radio, delay-sensitive cognitive radio, and simultaneously delay-insensitive and delay-sensitive cognitive radio, where a secondary user coexists with a primary user and the channels are fading. Using fractional programming and convex optimization techniques, energy-efficient optimal power allocation strategies are proposed subject to constraints on the average interference power, along with the peak/average transmit power. It is shown that the secondary user can achieve energy efficiency gains under the average transmit power constraint, in contrast to the peak transmit power constraint. Simulation results show that the fading of the channel between the primary user transmitter and the secondary user receiver and the fading of the channel between the secondary user transmitter and the primary user receiver are favorable to the secondary user with respect to the energy efficiency maximization of the secondary user, whereas the fading of the channel between the secondary user transmitter and the secondary user receiver is unfavorable to the secondary user.

The rapid development of modern communication services results in high data rate requirements from the end user. It is challenging to meet high data rate requirements because of prevailing issues such as spectrum scarcity and spectrum underutilization due to fixed spectrum assignment policy. Cognitive Radio (CR), being the enabler of dynamic spectrum management techniques, has the capability to tackle these issues by proficiently implementing spectrum sharing schemes using Multicarrier Modulation (MCM) techniques. In CR system, where the Primary User (PU) and the Secondary User (SU) co-exist in the same frequency band, mutual interference (i.e., from SU to PU and vice versa) is a limiting factor on the achievable capacity of both the PU and the SU. Power allocation in MCM based CR systems aims to dynamically control the transmit power on each subcarrier of the SU in order to reduce the mutual interference. Furthermore, combining multiple antennas with MCM is regarded as a very attractive solution for the CR communications to effectively enhance data rate without demanding additional bandwidth and transmit power.