Change search
ReferencesLink to record
Permanent link

Direct link
Multiantenna Cellular Communications: Channel Estimation, Feedback, and Resource Allocation
KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
2011 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

The use of multiple antennas at base stations and user devices is a key component in the design of cellular communication systems that can meet the capacity demands of tomorrow. The downlink transmission from base stations to users is particularly limiting, both from a theoretical and a practical perspective, since user devices should be simple and power-efficient, and because many applications primarily create downlink traffic (e.g., video streaming). The potential gain of employing multiple antennas for downlink transmission is well recognized: the total data throughput increases linearly with the number of transmit antennas if the spatial dimension is exploited for simultaneous transmission to multiple users. In the design of practical cellular systems, the actual benefit of multiuser multiantenna transmission is limited by a variety of factors, including acquisition and accuracy of channel information, transmit power, channel conditions, cell density, user mobility, computational complexity, and the level of cooperation between base stations in the transmission design.

The thesis considers three main components of downlink communications: 1) estimation of current channel conditions using training signaling; 2) efficient feedback of channel estimates; and 3) allocation of transmit resources (e.g., power, time and spatial dimensions) to users. In each area, the thesis seeks to provide a greater understanding of the interplay between different system properties. This is achieved by generalizing the underlying assumptions in prior work and providing both extensions of previous outcomes and entirely new mathematical results, along with supporting numerical examples. Some of the main thesis contributions can be summarized as follows.

A framework is proposed for estimation of different channel quantities using a common optimized training sequence. Furthermore, it is proved that each user should only be allocated one data stream and utilize its antennas for receive combining and interference rejection, instead of using the antennas for reception of multiple data streams. This fundamental result is proved under both exact channel acquisition and under imperfections from channel estimation and limited feedback. This also has positive implications on the hardware and system design.

Next, a general mathematical model is proposed for joint analysis of cellular systems with different levels of base station cooperation. The optimal multicell resource allocation can in general only be found with exponential computational complexity, but a systematic algorithm is proposed to find the optimal solution for the purpose of offline benchmarking. A parametrization of the optimal solution is also derived, creating a foundation for heuristic low-complexity algorithms that can provide close-to-optimal performance. This is exemplified by proposing centralized and distributed multicell transmission strategies and by evaluating these using multicell channel measurements.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology , 2011. , xv, 232 p.
Trita-EE, ISSN 1653-5146 ; 2011:072
Keyword [en]
channel estimation, limited feedback, multicell communications, resource allocation
National Category
URN: urn:nbn:se:kth:diva-45035OAI: diva2:451633
Public defence
2011-11-17, Hörsal K2, Teknikringen 28, KTH, Stockholm, 13:15 (English)
In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of KTH Royal Institute of Technology's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to to learn how to obtain a License from RightsLink. QC 20111026Available from: 2011-10-26 Created: 2011-10-26 Last updated: 2011-10-26Bibliographically approved

Open Access in DiVA

doctoral_thesis_emil_bjornson(4213 kB)1949 downloads
File information
File name FULLTEXT01.pdfFile size 4213 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Björnson, Emil
By organisation
Signal ProcessingACCESS Linnaeus Centre

Search outside of DiVA

GoogleGoogle Scholar
Total: 1949 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 2047 hits
ReferencesLink to record
Permanent link

Direct link