Eylem Seç
Radio Spectrum Virtualization in Wireless Mobile Networks
Başlık:
Radio Spectrum Virtualization in Wireless Mobile Networks
Yazar:
Zhang, Yingxiao, author.
ISBN:
9780438147980
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (138 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-11(E), Section: B.
Advisors: Ying-Jun Angela Zhang.
Özet:
Wireless network virtualization enables mobile virtual network operators (MVNOs) to develop new services on a low-cost platform by leasing network resources from mobile network owners. To maximize its surplus, an MVNO tries to, on the one hand, reduce the leasing cost on purchasing radio resources, and, on the other hand, utilize the acquired resources to provide high quality-of-service (QoS) to its mobile subscribers. Due to the broadcasting and stochastic nature of wireless channels, the virtualization of radio spectrum in the physical layer is more challenging than that of wired resources in upper layers. In this thesis, we identify the challenges in spectrum virtualization, and address them with novel spectrum leasing and utilization schemes.
First, we address the challenge of spectrum provisioning brought about by the uncertainty of mobile traffic and wireless channels. We propose a two-stage spectrum leasing framework, which allows an MVNO to acquire spectrum resources from both advance reservation and on-demand request. To maximize the MVNO's surplus, we jointly optimize the amount of spectrum resources to lease in the two stages by taking into account the traffic distribution, random user locations, wireless channel fading, QoS requirements, and price differences. Simulation results show that the derived two-stage leasing scheme can achieve more surplus than traditional one-stage leasing schemes under different levels of traffic and on-demand price variations.
Then, we shift to the spectrum utilization problem in dense networks. Network densification is a straightforward way to increase the overall network throughput with limited spectrum resources. However, aggressive frequency reuse creates severe inter-cell interference, and the gain from network densification is far less than expected. Hence, efficient coordination schemes are needed to mitigate strong interference in dense networks. In particular, we consider two emerging network densification technologies, cloud radio access network (CRAN) and heterogeneous network (HetNet).
In CRAN, dense remote radio head (RRHs) are centrally coordinated by a data center, where RRH cooperation can be configured flexibly on demand. Based on this feature, we develop a user-centric join transmission scheme, where a set of RRHs around a mobile user are configured as a small virtual cell. We derive the average user throughput in the downlink analytically. The result reveals the impact of important design parameters, such as RRH density, path-loss exponent, virtual cell size and the minimum separation distance between co-channel users.
In HetNet, interference comes from base stations (BSs) that have different transmit powers, number of antennas and coverage. Considering the limited backhaul connections between BSs, we develop a low-complexity inter-cell interference coordination (ICIC) scheme, where each multi-antenna BS adjusts its beamformer in order to avoid severe interference to a set of users in neighbor cells. We formulate the assignment problem of interference-nulling users to BSs as an integer programming, which can be solved efficiently by a greedy algorithm. Simulation results in a two-tier network show that the proposed ICIC scheme can balance the data rates in different cells adaptively such that the total network throughput is improved.
Notlar:
School code: 1307
Tüzel Kişi Ek Girişi:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(697044.1) | 697044-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.