Cooperative multi-cell networks: impact of limited-capacity backhaul and inter-users links (original) (raw)
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IEEE Transactions on Wireless Communications, 2000
Characterization and modeling of co-channel interference is critical for the design and performance evaluation of realistic multi-cell cellular networks. In this paper, based on alpha stable processes, an analytical co-channel interference model is proposed for multi-cell multiple-input multi-output (MIMO) cellular networks. The impact of different channel parameters on the new interference model is analyzed numerically.
Local Base Station Cooperation Via Finite-Capacity Links for the Uplink of Linear Cellular Networks
IEEE Transactions on Information Theory, 2000
Cooperative decoding at the base stations (or access points) of an infrastructure wireless network is currently well recognized as a promising approach for intercell interference mitigation, thus enabling high frequency reuse. Deployment of cooperative multicell decoding depends critically on the tolopology and quality of the available backhaul links connecting the base stations. This work studies a scenario where base stations are connected only if in adjacent cells, and via finite-capacity links. Relying on a linear Wyner-type cellular model with no fading, achievable rates are derived for the two scenarios where base stations are endowed only with the codebooks of local (in-cell) mobile stations, or also with the codebooks used in adjacent cells. Moreover, both uni-and bidirectional backhaul links are considered. The analysis sheds light on the impact of codebook information, decoding delay, and network planning (frequency reuse) on the performance of multicell decoding as enabled by local and finite-capacity backhaul links. Analysis in the high-signal-to-noise ratio (SNR) regime and numerical results validate the main conclusions.
Cooperative Wireless Cellular Systems: An Information-Theoretic View
Foundations and Trends® in Communications and Information Theory, 2011
In this monograph, the impact of cooperation on the performance of wireless cellular systems is studied from an information-theoretic standpoint, focusing on simple formulations typically referred to as Wynertype models. Following ongoing research and standardization efforts, the text covers two main classes of cooperation strategies. The first class is cooperation at the base station (BS) level, which is also known as Multi-Cell Processing (MCP), network Multiple-Input Multiple-Output (MIMO), or Coordinated Multi-Point transmission/reception (CoMP). With MCP, cooperative decoding, for the uplink, or encoding, for the downlink, is enabled at the BSs. MCP is made possible by the presence of an architecture of, typically wired, backhaul links connecting individual BSs to a central processor (CP) or to one another. The second class of cooperative strategies allows cooperation in the form of relaying for conveying data between Mobile Stations (MSs) and BSs in either the uplink or the downlink. Relaying can be enabled by two possible architectures. A first option is to deploy dedicated Relay Stations (RSs) that are tasked with forwarding uplink or downlink traffic. The second option is for the MSs to act as RSs for other MSs.
DOWNLINK PERFORMANCE OF 2CELL COOPERATION SCHEMES IN A MULTICELL ENVIRONMENT
Cooperative transmission schemes are used in wireless networks to improve the spectral efficiency. In a multi-cell environment, other cell interference (OCI) degrades the performance of wireless systems. In this paper, we study the performance of downlink sum rate for cell-edge users in a multi-cell environment under base station cooperation. The base-stations coordinate their transmission to the two cell-edge users in order to improve their Signal-to-interference-noise ratio (SINR) and throughput. Sum Capacity of cell-edge users for different transmit cooperation strategies is compared. Results show that Dirty Paper Coding (DPC) scheme, in a 2-cell cooperation, has significant gain in sum-rate compared to other cooperative schemes. However, when interference from all the other cells are considered, DPC performance is only marginally better than other low complexity cooperation schemes.
Low-SNR analysis of cellular systems with cooperative base stations and mobiles
2006 Fortieth Asilomar Conference on Signals, Systems and Computers, 2006
In this paper, joint (cooperative) decoding at the base stations combined with collaborative transmission at the mobile terminals is investigated as a means to improve the uplink throughput of current cellular systems over fading channels. Intra-cell orthogonal medium access control and Decodeand-Forward collaborative transmission among terminals are assumed. Moreover, the cellular system is modelled according to a simpli ed framework introduced by Wyner. The focus of this work is on low-power transmission (or equivalently on the wideband regime), where the ergodic per-cell throughput can be described by the minimum energy per bit required for reliable communication and the slope of the spectral ef ciency at low SNR. These two parameters are derived for different system con gurations and, capitalizing on the analysis, the relative merits of both cooperation among base stations and among terminals are assessed.
Uplink system capacity of a cellular network with cooperative mobile relay
2011 Wireless Telecommunications Symposium (WTS), 2011
This paper studies the performance of a hybrid cellular network with cellular controlled direct radio links between multiple mobile User Equipments (UEs). The main focus is on the downlink of the proposed system with multiple idle UEs acting as relays to assist the communication of any given UE with an active connection. In the presence of multiple UEs as relays, the Base Station (BS) dynamically chooses the best relay to maximize the throughput of each radio link. We present system capacity results using Monte Carlo system simulation techniques. Further, we compare results with and without the use of cooperating coding techniques. Our results indicate that cell edge capacity could be improved by more than 110% by using idle UEs in the system as mobile relays. The performance improvement at cell edge is achieved while improving the mean cell throughput by more than 50%.
Cellular Systems with Non-Regenerative Relaying and Cooperative Base Stations
IEEE Transactions on Wireless Communications, 2010
In this paper, the performance of cellular networks with joint multicell processing and dedicated relay terminals is investigated. It is assumed that each relay terminal is capable of full-duplex operation and receives the transmission of relay terminals in adjacent cells. Focusing on intra-cell time division multiple access and non-fading channels, a simplified relay-aided uplink cellular model is considered. Addressing the achievable per-cell sum-rate, two non-regenerative relaying schemes are considered. Interpreting the received signal at the base stations as the outcome of a two-dimensional linear time invariant system, the multicell processing rate of an amplify-and-forward scheme is derived and shown to decrease with the inter-relay interference level. A novel form of distributed compress-andforward scheme with decoder side information is then proposed. The corresponding multicell processing rate, which is given as a solution of a simple fixed-point equation, reveals that the compress-and-forward scheme is able to completely eliminate the inter-relay interference, and it approaches a "cut-set-like" upper bound for strong relay terminal transmission power. The benefits of base-station cooperation via multicell processing over the conventional single site processing approach is also demonstrated for both protocols. Index Terms-Non-regenerative relaying, amplify and forward, compress and forward, multicell processing. I. INTRODUCTION T HE ever growing demand for mobile data rate services and better coverage of cellular networks perpetuates massive research efforts aimed at developing new communication techniques. In this paper, we study the combination of two Manuscript
Throughput of cellular uplink with dynamic user activity and cooperative base-stations
2009 IEEE Information Theory Workshop, 2009
The throughput of a linear cellular uplink with a random number of users, different power control schemes, and cooperative base stations is considered in the large system limit where the number of cells is large for non fading Gaussian channels. The analysis is facilitated by establishing an analogy between the cellular channel per-cell throughput with joint multicell processing (MCP), and the rate of a deterministic intersymbol interference (ISI) channel with flat fading. It is shown that, under certain conditions, the dynamics of cellular systems (i.e., a random number of users coupled with a given power control scheme) can be interpreted, as far as the uplink throughput is concerned, as the flat fading process of the equivalent ISI channel. The results are used to demonstrate the benefits of MCP over the conventional single cell processing approach as a function of various system parameters in the presence of random user activity.
Throughput of Cellular Systems with Conferencing Mobiles and Cooperative Base Stations
EURASIP Journal on Wireless Communications and Networking, 2008
This paper considers an enhancement to multicell processing for the uplink of a cellular system, whereby the mobile stations are allowed to exchange messages on orthogonal channels of fixed capacity (conferencing). Both conferencing among mobile stations in different cells and in the same cell (inter-and intracell conferencing, resp.) are studied. For both cases, it is shown that a rate-splitting transmission strategy, where part of the message is exchanged on the conferencing channels and then transmitted cooperatively to the base stations, is capacity achieving for sufficiently large conferencing capacity. In case of intercell conferencing, this strategy performs convolutional pre-equalization of the signal encoding the common messages in the spatial domain, where the number of taps of the finite-impulse response equalizer depends on the number of conferencing rounds. Analysis in the low signal-to-noise ratio regime and numerical results validate the advantages of conferencing as a complementary technology to multicell processing.
Ad Hoc Cooperation for the Cellular Uplink with Capacity Constrained Backhaul
IEEE International Conference on Communications, 2010
Base station cooperation is a promising solution to the interference limitation of today's cellular networks. The capacity and fairness gains shown by information theoretical analysis of base station cooperation in cellular networks are huge. However, a major downside of base station cooperation is the additional information exchange among base stations which is the motivation for recent work on backhaul efficient