Survey on coexistence of heterogeneous wireless networks in 2.4 GHz and TV white spaces <s> Classification by domains <s> Emerging WLAN standards have been incorporating a variety of channel widths ranging from 5MHz to 160MHz, in order to match the diverse traffic demands on different networks. Unfortunately, the current 802.11 MAC/PHY is not designed for the coexistence of variable-width channels. Overlapping narrowband channels may block an entire wide-band channel, resulting in severe spectrum underutilization and even starvation of WLANs on the wide-band. A similar peril exists when a WLAN partially overlaps its channel with multiple orthogonal WLANs. In this paper, we propose to solve the problem of partial spectrum sharing using Adaptive Subcarrier Nulling (ASN). ASN builds on the 802.11 OFDM PHY, but allows the radios to sense, transmit, detect, and decode packets through spectrum fragments, or subbands. An ASN transmitter can adapt its spectrum usage on a per-packet basis, by nulling the subbands used by neighboring WLANs, and sending packets through the remaining idle subbands. ASN preserves the 802.11 CSMA/CA primitives while allowing users to contend for access to each subband, and can opportunistically exploit the merits of wide-band channels via spectrum aggregation. We have implemented and evaluated ASN on the GNURadio/USRP platform. Our experimental results have shown ASN to achieve detection and decoding performance comparable to the legacy 802.11. Our detailed simulation in ns-2 further shows that ASN substantially improves the efficiency and fairness of spectrum sharing for multi-cell WLANs. <s> BIB001 </s> Survey on coexistence of heterogeneous wireless networks in 2.4 GHz and TV white spaces <s> Classification by domains <s> Interference is a critical issue in wireless communications. In a typical multiple-user environment, different users may severely interfere with each other. Coordination among users therefore is an indispensable part for interference management in wireless networks. It is known that coordination among multiple nodes is a costly operation taking a significant amount of valuable communication resource. In this paper, we have an interesting observation that by generating intended patterns, some simultaneous transmissions, i.e., "interference,” can be successfully decoded without degrading the effective throughput in original transmission. As such, an extra and "free” coordination channel can be built. Based on this idea, we propose a DC-MAC to leverage this "free” channel for efficient medium access in a multiple-user wireless network. We theoretically analyze the capacity of this channel under different environments with various modulation schemes. USRP2-based implementation experiments show that compared with the widely adopted CSMA, DC-MAC can improve the channel utilization efficiency by up to 250 percent. <s> BIB002 </s> Survey on coexistence of heterogeneous wireless networks in 2.4 GHz and TV white spaces <s> Classification by domains <s> Cognitive radio (CR) technologies have led to several wireless standards (e.g., IEEE 802.11af and IEEE 802.22) that enable secondary networks to access the TV white-space (TVWS) spectrum. Different unlicensed wireless technologies with different PHY/MAC designs are expected to coexist in the same TVWS spectrum-we refer to such a situation as heterogeneous coexistence. The heterogeneity of the PHY/MAC designs of coexisting CR networks can potentially exacerbate the hidden terminal problem. This problem cannot be addressed by the conventional handshaking/coordination mechanism between two homogeneous networks employing the same radio access technology. In this paper, we present a coexistence protocol, called Spectrum Sharing for Heterogeneous Coexistence (SHARE), that mitigates the hidden terminal problem for the coexistence between two types of networks: one that employs a time-division-multiplexing-based MAC protocol and one that employs a carrier-sense-multiple-access-based MAC protocol. Specifically, SHARE utilizes beacon transmissions and dynamic quiet periods to avoid packet collisions caused by the hidden terminals. Our analytical and simulation results show that SHARE reduces the number of packet collisions and guarantees weighted fairness in partitioning the spectrum among the coexisting secondary networks. <s> BIB003 </s> Survey on coexistence of heterogeneous wireless networks in 2.4 GHz and TV white spaces <s> Classification by domains <s> Coexistence protocols enable collocated cognitive radio networks (CRNs) to share the spectrum in an opportunistic manner. These protocols work under the assumption that all spectrum bands provide the same level of throughput. This assumption is however limited in scope because channel conditions as well as the licensee's usage of allocated channels can vary significantly with time and space. Under these circumstances, CRNs are expected to have a preference over the choice of available channels which can lead to an imbalance in contention for disparate channels, degraded quality of service, and an overall inefficient utilization of spectrum resource. In this paper, we analyze this situation from a game theoretic perspective and model the coexistence of CRNs with heterogeneous spectrum as a non-cooperative, repeated spectrum sharing game. We derive three solutions for the game; (1) pure and (2) mixed strategy Nash Equilibria as well as (3) centralized and distributed correlated equilibria which are derived using linear programming and a channel selection learning algorithms, respectively. We also analyze each of these solutions from the perspective of fairness and efficiency. To that end, we utilize the concept of price of anarchy to measure the efficiency of these solutions under selfish behavior from CRNs. <s> BIB004 </s> Survey on coexistence of heterogeneous wireless networks in 2.4 GHz and TV white spaces <s> Classification by domains <s> In this paper, we focus on spectrum sharing in heterogeneous wireless sensor networks (HWSNs) and consider Stackelberg game exploiting the cognitive radio (CR) technology to utilize those scarce resources. In the game, the licensed network controls and prices the available spectrum resource which the WSN relay: actor nodes can purchase and use to serve the attached sensor nodes as well as offload some nodes in licensed network. Both kinds of nodes try to maximize their own utility which is consisted of data rates, earning and expenditures on spectrum trading. During the dynamic interaction of the game, the interference coordination features of the heterogeneous sensor network and CR technology are employed so that the change of spectrum allocation can be fully exploited. According to simulation result, we evaluate the impact on throughput performance after implementing proposed game strategy in HWSN. And we prove that the proposed approach can significantly improve the throughput of victim licensed nodes with slightly decreasing network total throughput. HighlightsWe focus on spectrum sharing in heterogeneous wireless sensor networks (HWSNs) and consider Stackelberg game exploiting the cognitive radio (CR) technology to utilize those scarce resources. In our scheme, the licensed user impose a price on the shared frequency band and the cognitive radio sensor network (CRSN) nodes have to buy the band to serve their own networks. As the dynamic game continues, equilibrium can be achieved with the optimal parameters.Introducing Stackelberg game enables the licensed network and actor nodes act dynamically and intelligently to handle the frequency allocation issue, and makes the underlying HWSN work in a self-organized manner.The data rate of the victim nodes and edge nodes is guaranteed due to the proposed scheme. During the dynamic interaction of the algorithm, because of employing the interference coordination features of HWSN and CR technology, the change of spectrum allocation is fully exploited.The frequency resources can be allocated efficiently and adaptively to licensed network and actor nodes in response to the dynamic status of nodes density. <s> BIB005
However, coexistence mechanisms for the heterogeneous wireless networks are distinctive with each other, but they could also be classified into different domains which their coexistence approaches work in. Then, we would like to introduce some representative solutions under time, frequency and code domains in this part. Coexistence in time domain. In this class of coexistence solutions, each coexisting network gets a time share of the total radio resource. A coordination protocol is required to negotiate how time is shared among coexisting networks, so that the collision can be avoided. A representative coexistence solution in time domain is the SHARE mechanism developed by Bian et al. BIB003 SHARE divides communication time slots into different types in order to carry the frames of different networks. An algorithm is developed to allocate time slots among coexisting networks with the objective of achieving fairness among them. And in the work by Amjad et al., BIB004 heterogeneous CR networks' data transmission periods are split into equal small time slots and allocated in appropriate channels by game-based algorithm, so that data collisions between CR networks could be minimized and coexistence is realized. Coexistence in frequency domain. Another coexistence solution is to allow coexisting networks to coexist in the frequency domain. Specifically, they are required to coordinate their operation frequencies in order to switch to non-overlapping channels. A coexistence mechanism in the frequency domain is provided by Zhang and Shin BIB001 where ASN mechanism is developed to divide a channel into several subbands and to regulate the coexistence on the basis of subbands. While in the work by Sun et al., BIB005 a novel spectrum sharing mechanism is proposed for coordinating licensed users and CR sensor networks' spectrum shares and data rate through utilizing Stackelberg game theory in order to improve victim nodes' overall throughput. Coexistence in code domain. This type of solutions is based on code domain, and by utilizing specific codes, a side channel could be constructed for transmitting control messages on top of data packets. As an example, Wu et al. BIB002 proposed to create a side control channel through special interference codes on top of data communication.