Access Point Placement for Hybrid UAV-Terrestrial Small-Cell Networks
Access Point Placement for Hybrid UAV-Terrestrial Small-Cell Networks
复制标题
混合无人机-地面小蜂窝网络的接入点布局
DOI：
10.1109/ojcoms.2021.3100060
复制
发表时间：
2021
影响因子：
7.9
通讯作者：
Villardi, Gabriel Porto
中科院分区：
文献类型：
--
作者：
Gopal, Govind R.;Rao, Bhaskar D.;Villardi, Gabriel Porto
我们解决了在具有部分基础设施灵活性的小蜂窝网络中放置接入点(AP)的问题，即，由于使用具有AP功能的无人机(UAV-AP)来帮助固定无线网络应对瞬时峰值容量需求，在Beyond 5G中产生了一类新的问题。我们使用信干噪比(SGINR)来替代传统的信干噪比(SINR)来量化小区间干扰(ICI)对每个用户容量的影响。根据平均SGINR，我们推导出ICI感知失真度量，从而导致AP间Lloyd算法为完全灵活的基础设施获得吞吐量最优的AP位置。然后，我们对AP布局问题施加了混合约束，将网络的一小部分变成由地面AP(T-AP)组成的固定基础设施，而其余的则由位置灵活的UAV-AP组成。提出了一种称为混合AP布局算法(HAPPA)的Lloyd型算法来解决这种新的AP布局问题。此外，我们还提出了一种用于混合高斯模型(GMM)的Lloyd和Lloyd型算法的初始化方法，该方法提供了比k-Means++初始化更高的AP分配。最后，计算机仿真表明，在网络完全灵活的情况下，AP间Lloyd算法可以将最差用户的性能提高高达42.75%。通过在混合网络上使用HAPPA，当使用相同数量的UAV-AP和T-AP时，我们获得了比固定网络高达71.92%的总和率改进，并缩小了与完全灵活网络的性能差距至2.02%。此外，我们提出的初始化方案总是导致平衡的AP分配，这意味着每个AP的用户分布更加均匀，而k-Means++方案至少在30%的时间内导致不平衡的分配，从而导致更差的最小速率。
We address the problem of access point (AP) placement in small-cell networks with partial infrastructure flexibility, i.e., a novel class of problem in Beyond 5G, resultant from the utilization of unmanned aerial vehicles (UAVs) with AP functionalities (UAV-APs), to aid fixed wireless networks in coping with momentary peak-capacity requirements. We use the signal-to-generated-interference-plus-noise ratio (SGINR) metric as an alternative to the traditional signal-to-interference-plus-noise ratio (SINR) to quantify the effects of inter-cell interference (ICI) on the per-user capacity. From average SGINR, we derive the ICI-aware distortion measure leading to the Inter-AP Lloyd algorithm to obtain throughput-optimal AP placement for a fully flexible infrastructure. We then impose a hybridity constraint to the AP placement problem which turns a fraction of the network into a fixed infrastructure composed of terrestrial APs (T-APs) while the remainder is constituted by UAV-APs with flexibility in position. This newly formulated AP placement problem is solved by the proposed Lloyd-type algorithm called Hybrid AP Placement Algorithm (HAPPA). Furthermore, we present an initialization method for the Lloyd and Lloyd-type algorithms for Gaussian mixture models (GMMs) that offers an AP allocation leading to a higher rate compared to the k-means++ initialization. Finally, computer simulations show that the Inter-AP Lloyd algorithm can improve the performance of the worst users by up to 42.75% in achievable rate, assuming a fully flexible network. By using HAPPA on hybrid networks, we achieve improvements of up to 71.92% in sum rate over the fixed network and close the performance gap with fully flexible networks down to 2.02%, when an equal number of UAV-APs and T-APs is used. Further, our proposed initialization scheme always results in a balanced AP allocation, which means a more even distribution of users per AP, whereas the k-means++ scheme results in unbalanced allocations at least 30% of the time, resulting in a worse minimum rate.