Primary-secondary spectrum sharing is limited in terms of design space, and may not be sufficient to meet the ever-increasing demand of connectivity and high signal quality. The next step to increase spectrum sharing efficiency is to design markets where sharing takes place among primary providers rather than leaving it to the limited case where the primary licensee is idle. Attaining contractual spectrum sharing among primary providers, a.k.a. co-primary or inter-provider sharing, involves additional costs for the users, e.g., roaming fee. Co-primary spectrum sharing without additional charge to the users poses two major challenges: a) regulatory approaches must be introduced to incentivize providers to share spectrum resources, and b) small providers in co-primary spectrum sharing markets may freeride on large providers’ networks as the customers of the small providers may be using the spectrum and infrastructure resources of large providers. Such freeriding opportunities must be minimized to realize the benefits of primary-level sharing. We consider a subsidy-based spectrum sharing (SBSS) market to facilitate co-primary spectrum sharing where providers are explicitly incentivized to share spectrum resources. We focus on minimizing freeriding in SBSS markets and introduce a game-theoretic model to regulate the freeriding. We use the model to explore operational regimes with minimal freeriding.

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A Game-Theoretic Framework to Regulate Freeriding in Inter-Provider Spectrum Sharing

With the emergence of the adaptive bit rate (ABR) streaming technology, the video/content streaming technology is shifting toward a file-based content distribution. That is, video content is encoded into a set of smaller media files containing video of 2–10 seconds before transmission. This file-based content distribution, coupled with increasingly rapid adoption of smartphones, requires an efficient file-based distribution algorithm to satisfy the QoS demand in wireless networks. In this paper, we study the transmission of a finite-sized file over wireless networks using multipath routing, with the objective to minimize file transmission delay instead of average packet delay. The file transmission delay is defined as the time interval from the instant that a file is first transmitted to the time at which the file can be reconstructed in the destination node. We observe that file transmission delay depends not only on the mean of the packet delay but also on its distribution, especially the tail. This observation leads to a better understanding of the file transfer delay in wireless networks and a minimum delay file transmission strategy. In a wireless multipath communication scenario, we propose to use packet level erasure code (e.g., digital fountain code) to transmit data file with redundancy. Given that a file with k packets is encoded into n packets for transmission, the use of digital fountain code allows the file to be received when only k out of n packets are received. By adding redundant packets, the destination node does not have to wait for the packet to arrive late, hence reducing the delay of the file transmission. We characterize the tradeoff between the code rate (i.e., the ratio of the number of transmitted packets to the number of the original packets) and the file delay reduction. As a rule of thumb, we provide practical guidelines in determining an appropriate code rate for a fixed file to achieve a reasonable transmission delay. We show that only a few redundant packets are needed to achieve a significant reduction in file transmission delay.

On file-based content distribution over wireless networks via multiple paths: Coding and delay trade-off

This paper presents spectrum management in dynamic spectrum access (DSA) based 5G heterogeneous wireless networks (HetNets). Current literature studies architectures and signaling mechanisms for network selection, but rarely discuss proper bandwidth management for users over multiple HetNets. This paper considers users connected to multiple service providers in HetNets. A non-cooperative game is presented to determine the optimal bandwidth required at each service provider. The existence of a unique Nash equilibrium is shown. Results indicate that optimal allocation of spectrum is achieved when fairness is achieved. in other words, bandwidth available at any service provider is allocated equally to all users. This agrees with some empirical experimental studies available in the literature. Results also show that the proposed approach reduces user churning rate1, compared to traditional spectrum management approaches. The improvement is about 22–50% for delay intolerant traffic and 15-65% for delay tolerant traffic.1Defined as the percentage of users that do not meet the quality-of-service.

Vijay P. Kumar

Papers

Spectrum Management over Dynamic Spectrum Access based HetNets