Interoperator Opportunistic Spectrum Sharing in LTE-Unlicensed

Abstract

This paper studies how to maximize the per-user-based throughput in an M-tier heterogeneous wireless network (HetNet) by optimally managing traffic flows among the access points (APs) in the HetNet. The APs in the first M − 1 tiers can use the licensed spectrum at the same time whereas they share the unlicensed spectrum with the APs in the M th tier by the proposed opportunistic CSMA/CA protocol. We characterize the statistical property of the cell load and channel access probability of each AP using a general AP association scheme. For an AP in each tier, the tight bounds on its mean spectrum efficiencies in the licensed and unlicensed spectra are derived in a low-complexity form for general random channel gain and AP association weight models and they can give some insights on how channel gains, AP association weights and void AP probabilities affect the mean spectrum efficiencies. We define the per-user link throughput and per-user network throughput based on the derived the mean spectrum efficiencies and maximize them by proposing the decentralized and centralized traffic management schemes for the APs in the first M − 1 tiers under the constraint that the per-user link throughput of the tier-M APs must be above some minimum required value. Finally, a numerical example of coexisting LTE and WiFi networks is provided to validate our derived results and findings.

RRC State Handling for 5G

“…Static frequency domain orthogonal spectrum sharing is widely used by regulatory bodies to allocate licensed spectrum to operators [39]. Dynamic frequency domain orthogonal spectrum sharing is shown to improve the performance of static sharing [40][41][42]. Time domain orthogonal spectrum sharing is often used for unlicensed spectrum sharing where transmitters are allowed to use a common resource pool but only a single transmitter at a time.…”

Resource allocation for licensed and unlicensed spectrum in 5G heterogeneous networks

“…Dynamic channel selection mechanisms are proposed in other works [24][25][26][27][28][29][30][31][32] for WiFi-LTE coexistence. Ibars et al 24 proposed a centralized algorithm for channel selection in LTE-U.…”

“…In the work of Voicu et al, interference‐aware channel selection techniques are proposed for outdoor LTE‐U pico and indoor WiFi cells. Jiang and Mao proposed an algorithm for opportunistic spectrum sharing among LTE‐U BSs, while guaranteeing the quality of service (QoS) of UEs. They have used the Lyapunov optimization method to evaluate the value of unlicensed spectrum, while guaranteeing the thresholds of packet drop rate and delay.…”

Enabling LTE and WiFi Coexisting in 5 GHz for Efficient Spectrum Utilization

“…To improve LTE-U method, [26][27][28][29][30] make a more careful design of LTE-U to increase the throughput of WiFi devices. Reference [31] proposed a novel distributed algorithm for opportunistic sharing of unlicensed bands among LTE and WiFi devices (more details related to LTE-U are discussed in Section 3).…”