Results 1 - 10
of
56
Networked MIMO with Clustered Linear Precoding
, 2008
"... A clustered base transceiver station (BTS) coordination strategy is proposed for a large cellular MIMO network, which includes full intra-cluster coordination–to enhance the sum rate–and limited inter-cluster coordination–to reduce interference for the cluster edge users. Multi-cell block diagonaliz ..."
Abstract
-
Cited by 93 (18 self)
- Add to MetaCart
A clustered base transceiver station (BTS) coordination strategy is proposed for a large cellular MIMO network, which includes full intra-cluster coordination–to enhance the sum rate–and limited inter-cluster coordination–to reduce interference for the cluster edge users. Multi-cell block diagonalization is used to coordinate the transmissions across multiple BTSs in the same cluster. To satisfy per-BTS power constraints, three combined precoder and power allocation algorithms are proposed with different performance and complexity tradeoffs. For inter-cluster coordination, the coordination area is chosen to balance fairness for edge users and the achievable sum rate. It is shown that a small cluster size (about 7 cells) is sufficient to obtain most of the sum rate benefits from clustered coordination while greatly relieving channel feedback requirement. Simulations show that the proposed coordination strategy efficiently reduces interference and provides a considerable sum rate gain for cellular MIMO networks.
1 Adaptive Spatial Intercell Interference Cancellation in Multicell Wireless Networks
, 909
"... Downlink spatial intercell interference cancellation (ICIC) is considered for mitigating other-cell interference using multiple transmit antennas. A principle question we explore is whether it is better to do ICIC or simply standard single-cell beamforming. We explore this question analytically and ..."
Abstract
-
Cited by 29 (8 self)
- Add to MetaCart
(Show Context)
Downlink spatial intercell interference cancellation (ICIC) is considered for mitigating other-cell interference using multiple transmit antennas. A principle question we explore is whether it is better to do ICIC or simply standard single-cell beamforming. We explore this question analytically and show that beamforming is preferred for all users when the edge SNR (signal-to-noise ratio) is low (< 0 dB), and ICIC is preferred when the edge SNR is high (> 10 dB), for example in an urban setting. At medium SNR, a proposed adaptive strategy, where multiple base stations jointly select transmission strategies based on the user location, outperforms both while requiring a lower feedback rate than the pure ICIC approach. The employed metric is sum rate, which is normally a dubious metric for cellular systems, but surprisingly we show that even with this reward function the adaptive strategy also improves fairness. When the channel information is provided by limited feedback, the impact of the induced quantization error is also investigated. It is shown that ICIC with well-designed feedback strategies still provides significant throughput gain. Index Terms Cellular network, other-cell interference, base station coordination, interference cancellation, limited feedback. I.
On the accuracy of the Wyner model in cellular networks,” submitted, 2010, available at: arxiv.org/abs/1009.5900
"... Abstract—The Wyner model has been widely used to model and analyze cellular networks due to its simplicity and analytical tractability. Its key aspects include fixed user locations and the deterministic and homogeneous interference intensity. While clearly a significant simplification of a real cell ..."
Abstract
-
Cited by 25 (13 self)
- Add to MetaCart
Abstract—The Wyner model has been widely used to model and analyze cellular networks due to its simplicity and analytical tractability. Its key aspects include fixed user locations and the deterministic and homogeneous interference intensity. While clearly a significant simplification of a real cellular system, which has random user locations and interference levels that vary by several orders of magnitude over a cell, a common presumption by theorists is that the Wyner model nevertheless captures the essential aspects of cellular interactions. But is this true? To answer this question, we compare the Wyner model to a model that includes random user locations and fading. We consider both uplink and downlink transmissions and both outage-based and average-based metrics. For the uplink, for both metrics, we conclude that the Wyner model is in fact quite accurate for systems with a sufficient number of simultaneous users, e.g., a CDMA system. Conversely, it is broadly inaccurate otherwise. Turning to the downlink, the Wyner model becomes inaccurate even for systems with a large number of simultaneous users. In addition, we derive an approximation for the main parameter in the Wyner model – the interference intensity term, which depends on the path loss exponent.
Distributed Compression for MIMO Coordinated Networks with a Backhaul Constraint
"... Abstract—We consider the uplink of a backhaul-constrained, MIMO coordinated network. That is, a single-frequency network with ..."
Abstract
-
Cited by 19 (1 self)
- Add to MetaCart
(Show Context)
Abstract—We consider the uplink of a backhaul-constrained, MIMO coordinated network. That is, a single-frequency network with
A WiMAX-based implementation of network MIMO for indoor wireless systems
- EURASIP Journal on Advances in Signal Processing
, 2009
"... It is well known that multiple-input multiple-output (MIMO) techniques can bring numerous benefits, such as higher spectral efficiency, to pointto-point wireless links. More recently, there has been interest in extending MIMO concepts to multiuser wireless systems. Our focus in this paper is on netw ..."
Abstract
-
Cited by 12 (6 self)
- Add to MetaCart
(Show Context)
It is well known that multiple-input multiple-output (MIMO) techniques can bring numerous benefits, such as higher spectral efficiency, to pointto-point wireless links. More recently, there has been interest in extending MIMO concepts to multiuser wireless systems. Our focus in this paper is on network MIMO, a family of techniques whereby each end user in a wireless access network is served through several access points within its range of influence. By tightly coordinating the transmission and reception of signals at multiple access points, network MIMO can transcend the limits on spectral efficiency imposed by cochannel interference. Taking prior informationtheoretic analyses of network MIMO to the next level, we quantify the spectral efficiency gains obtainable under realistic propagation and operational conditions in a typical indoor deployment. Our study relies on detailed simulations and, for specificity, is conducted largely within the physical-layer framework of the IEEE 802.16e Mobile WiMAX system. Furthermore, to facilitate the coordination between access points, we assume that a high-1 capacity local area network, such as Gigabit Ethernet, connects all the access points. Our results confirm that network MIMO stands to provide a multiple-fold increase in spectral efficiency under these conditions. 1
Coordinated Multi-cell MIMO Systems with Cellular
"... Abstract — A clustered base transceiver station (BTS) coordination strategy is proposed to realize the gains of multiuser MIMO communication in interference-limited cellular systems. In the proposed coordination strategy, users are divided into two groups: a full intra-cluster coordination group to ..."
Abstract
-
Cited by 9 (2 self)
- Add to MetaCart
(Show Context)
Abstract — A clustered base transceiver station (BTS) coordination strategy is proposed to realize the gains of multiuser MIMO communication in interference-limited cellular systems. In the proposed coordination strategy, users are divided into two groups: a full intra-cluster coordination group to enhance the sum rate gain and a limited inter-cluster coordination group to reduce interference for the cluster edge users. Multi-cell block diagonalization is used to coordinate the transmissions across multiple BTSs in the same cluster. Because of the per-BTS power constraints, three combined precoder and power allocation algorithms are considered in this paper with different performance complexity tradeoffs. Simulations show that the proposed coordination strategy improves the sum rate over conventional systems and reduces the impact of interference for the cluster-edge users. I.
Joint beamforming and power control in coordinated multicell: Max-min duality, effective network and large system transition
- IEEE TRANS. WIRELESS COMMUN
, 2013
"... This paper studies joint beamforming and power control in a coordinated multicell downlink system that serves multiple users per cell to maximize the minimum weighted signal-to-interference-plus-noise ratio. The optimal solution and distributed algorithm with geometrically fast convergence rate are ..."
Abstract
-
Cited by 8 (1 self)
- Add to MetaCart
(Show Context)
This paper studies joint beamforming and power control in a coordinated multicell downlink system that serves multiple users per cell to maximize the minimum weighted signal-to-interference-plus-noise ratio. The optimal solution and distributed algorithm with geometrically fast convergence rate are derived by employing the nonlinear Perron-Frobenius theory and the multicell network duality. The iterative algorithm, though operating in a distributed manner, still requires instan-taneous power update within the coordinated cluster through the backhaul. The backhaul information exchange and message passing may become prohibitive with increasing number of transmit antennas and increasing number of users. In order to derive asymptotically optimal solution, random matrix theory is leveraged to design a distributed algorithm that only requires statistical information. The advantage of our approach is that there is no instantaneous power update through backhaul. More-over, by using nonlinear Perron-Frobenius theory and random matrix theory, an effective primal network and an effective dual network are proposed to characterize and interpret the asymptotic solution.
A decentralized framework for dynamic downlink base station cooperation
- in Proc. IEEE Globecom’09
"... Abstract — Multiple Base Station (Multi-BS) cooperation has been considered as a promising mechanism to suppress co-channel interference and boost the capacity for cellular networks. However, the large feedback and signaling overhead hinder it from practice. Therefore, limited cooperation among BSs ..."
Abstract
-
Cited by 6 (3 self)
- Add to MetaCart
(Show Context)
Abstract — Multiple Base Station (Multi-BS) cooperation has been considered as a promising mechanism to suppress co-channel interference and boost the capacity for cellular networks. However, the large feedback and signaling overhead hinder it from practice. Therefore, limited cooperation among BSs is recognized as a good tradeoff between the performance gain and the relevant cost. In this paper, the whole network is divided into small disjointing BS cooperation groups, namely, clusters. A decentralized framework is proposed to facilitate the BS cluster formation on the downlink, in order to maximize the sum-rate of the scheduled mobile stations (MSs) under the cluster size constraint. Moreover, an efficient BS negotiation algorithm is designed for cluster formation, of which the feedback overhead per MS is irrelevant to the network size, and the number of iteration rounds scales very slowly with the network size. Simulations show that our strategy leads to significant sum-rate gain over static clustering and performs almost the same as the centralized greedy approach. With its low signaling overhead and complexity, the proposed framework is well suited for implementation in large-scale cellular networks. 1 I.
A scalable limited feedback design for network MIMO using per-cell product codebook
- IEEE Trans. Wirel. Commun
, 2010
"... ar ..."
Coordinate beamforming with relaxed zero forcing: The sequential orthogonal projection combining method and rate control
- Mar. 2012 [Online]. Available: http:// arxiv.org/abs/1203.1758,, ArXiv Pre-Print cs.IT/1203.1758
"... Abstract—In this paper, a new beam design paradigm for coordinated beamforming (CB) for current and future cellular networks is proposed based on a relaxed zero-forcing (RZF) constraint. In the conventional zero-forcing (ZF) CB, each co-operating transmitter designs its transmit beamforming matrix t ..."
Abstract
-
Cited by 4 (4 self)
- Add to MetaCart
(Show Context)
Abstract—In this paper, a new beam design paradigm for coordinated beamforming (CB) for current and future cellular networks is proposed based on a relaxed zero-forcing (RZF) constraint. In the conventional zero-forcing (ZF) CB, each co-operating transmitter designs its transmit beamforming matrix to null out interference to undesired receivers completely. In the proposed RZF paradigm, however, the ZF constraint is relaxed so that a tolerable amount of interference leakage to undesired receivers is allowed for the beam design at each transmitter. By relaxing the ZF constraint in such a way, transmitters have more degrees of freedom for their beam design to increase the overall data rate of the network. An efficient algorithm for the RZFCB is proposed based on a projected subgradient method. Numerical results show that the proposed RZFCB shows a noticeable gain over the conventional ZFCB. Index Terms—Coordinated beamforming, MIMO system, Zero-forcing, Interference channel, Projected subgradient method.
