Tractable Resource Management With Uplink Decoupled Millimeter-Wave Overlay in Ultra-Dense Cellular Networks

Abstract

The forthcoming 5G cellular network is expected to overlay millimeter-wave (mmW) transmissions with the incumbent micro-wave (µW) architecture. The overall mm-µW resource management should therefore harmonize with each other. This paper aims at maximizing the overall downlink (DL) rate with a minimum uplink (UL) rate constraint, and concludes: mmW tends to focus more on DL transmissions while µW has high priority for complementing UL, under time-division duplex (TDD) mmW operations. Such UL dedication of µW results from the limited use of mmW UL bandwidth due to excessive power consumption and/or high peak-to-average power ratio (PAPR) at mobile users. To further relieve this UL bottleneck, we propose mmW UL decoupling that allows each legacy µW base station (BS) to receive mmW signals. Its impact on mm-µW resource management is provided in a tractable way by virtue of a novel closed-form mm-µW spectral efficiency (SE) derivation. In an ultra-dense cellular network (UDN), our derivation verifies mmW (or µW) SE is a logarithmic function of BS-to-user density ratio. This strikingly simple yet practically valid analysis is enabled by exploiting stochastic geometry in conjunction with real three dimensional (3D) building blockage statistics in Seoul, Korea.

Stochastic Geometric Coverage Analysis in mmWave Cellular Networks With Realistic Channel and Antenna Radiation Models

“…The UE density is assumed to be sufficiently large such that each BS has at least one associated UE. Multiple UEs can be associated with a single BS, while the BS serves only a single UE per unit time slot according to a uniformly random scheduler, as assumed in [1], [8], [11] under stochastic geometric settings. Out of these serving users in the network, we hereafter focus on a reference user that is located in the origin of the area considered, and is denoted as the typical UE.…”

Joint caching policies for optimizing energy costs/offloading probability for D2D and millimeter‐wave small cell underlaying cache‐enabled networks

“…MmWave signals are more sensitive to blockages, as certain materials like concrete walls found on building exteriors cause severe penetration loss. In this paper, we adopt the average LOS model proposed by Bai and Heath and Park et al The downlink is in LOS state when the distance between a typical user and its associated mm SBS is less than r L , and otherwise it is in non‐LOS (NLOS) state.…”

“…In this paper, we adopt the average LOS model proposed by Bai and Heath 29 and Park et al 30 The downlink is in LOS state when the distance between a typical user and its associated mmSBS is less than r L , and otherwise it is in non-LOS (NLOS) state. Furthermore, recent studies have shown that with highly directional transmissions and sensitivity to blockage, a positive side effect is that interference is greatly reduced, and so in many or most cases, mmWave networks will be noise rather than interference limited.…”

Performance Analysis and Optimization of Cache-Enabled Small Cell Networks

“…Unlike the conventional sub-6 GHz counterpart, mmWave transmissions are highly sensitive to the blockage. According to the average line-ofsight (LOS) model in [11][12][13], we consider that the mmWave link is LOS if the communication distance is less than D L , and otherwise it is non-line-of-sight (NLOS). Moreover, the existing literature has confirmed that mmWave transmissions tend to be noise-limited and interference is weak [11,13].…”