## Multi-user diversity vs. accurate channel feedback for mimo broadcast channel”, submitted to (2008)

Venue: | IEEE ICC |

Citations: | 13 - 2 self |

### BibTeX

@ARTICLE{Ravindran08multi-userdiversity,

author = {Niranjay Ravindran and Nihar Jindal},

title = {Multi-user diversity vs. accurate channel feedback for mimo broadcast channel”, submitted to},

journal = {IEEE ICC},

year = {2008}

}

### OpenURL

### Abstract

Abstract — A multiple transmit antenna, single receive antenna (per receiver) downlink channel with limited channel feedback is considered. Given a constraint on the total system-wide channel feedback, the following question is considered: is it preferable to get low-rate feedback from a large number of receivers or to receive high-rate/high-quality feedback from a smaller number of (randomly selected) receivers? Acquiring feedback from many users allows multi-user diversity to be exploited, while highrate feedback allows for very precise selection of beamforming directions. It is shown that systems in which a limited number of users feedback high-rate channel information significantly outperform low-rate/many user systems. While capacity increases only double logarithmically with the number of users, the marginal benefit of channel feedback is very significant up to the point where the CSI is essentially perfect. I.

### Citations

343 |
On the achievable throughput of a multiantenna Gaussian broadcast channel
- Caire, Shamai
- 2003
(Show Context)
Citation Context ...roadcast channels have been the subject of a tremendous amount of research since the seminal work of Caire and Shamai showed the sum-rate optimality of dirtypaper precoding (DPC) with Gaussian inputs =-=[1]-=-. If the transmitter is equipped with M antennas, then multi-user MIMO techniques (such as DPC or sub-optimal but low-complexity linear precoding) that allow simultaneous transmission to multiple user... |

185 | On the Capacity of MIMO Broadcast Channels with Partial Side Information
- Sharif, Hassibi
- 2005
(Show Context)
Citation Context ...ve been shown to be able to operate near capacity with extremely low-rate channel feedback in the asymptotic limit as the number of users is taken to infinity. In particular, random beamforming (RBF) =-=[6]-=- can operate with only log2 M bits of feedback per user (plus one real number). The performance of this technique in the asymptotic limit is quite amazing: not only does the ratio of random beamformin... |

129 | On The Optimality of Multiantenna Broadcast Scheduling Using Zero-Forcing Beamforming
- Yoo, Goldsmith
- 2006
(Show Context)
Citation Context ...( )) T 2 B term captures the effect of multiuser diversity due to T B users (as well as appropriate scaling with SNR and M) for ZF with perfect CSIT. This is ( asymptotically correct, to an O(1) term =-=[15]-=-. The M log2 1 + P M log ( ) T − B 2 B ) M−1 term serves to capture the throughput loss due to limited channel feedback, relative to perfect CSIT. [ The ( effect of finite rate feedback was quantified... |

98 | MIMO Broadcast Channels with Finite Rate Feedback
- Jindal
- 2006
(Show Context)
Citation Context ...mation theoretic perspective [2], as well as in terms of particular transmit strategies. In particular, zero-forcing beamforming has been shown to require CSIT quality that scales proportional to SNR =-=[3]-=-[5]. Large systems have been shown to be able to operate near capacity with extremely low-rate channel feedback in the asymptotic limit as the number of users is taken to infinity. In particular, rand... |

92 | Sum power iterative water-filling for multi-antenna gaussian broadcast channels
- Jindal, Rhee, et al.
- 2005
(Show Context)
Citation Context ...of the random vector quantization scheme with optimized B, for very large T . This is compared to the sum capacity of the T -user system with CSIT (computed using the iterative waterfilling algorithm =-=[16]-=-) as well as Zero forcing with greedy selection among T users and perfect CSIT. The advantage relative to random beamforming is maintained, due to the slow convergence of RBF. As a generalization of r... |

51 | On downlink beamforming with greedy user selection: performance analysis and a simple new algorithm
- Dimic, Sidiropoulos
- 2005
(Show Context)
Citation Context ...ropic distribution on the M-dimensional unit sphere [4] (RVQ). Each user is assumed to use a different and independently generated codebook1 . The transmitter uses lowcomplexity greedy user selection =-=[13]-=- along with zero-forcing 1 Note that random vector quantization allows us to simulate large quantization codebooks using the statistics of the quantization error (which is known), permitting a Monte C... |

39 | Zoltowski,“Multiple antenna broadcast channels with partial and limited feedback
- Ding, Love, et al.
- 2005
(Show Context)
Citation Context ...ion theoretic perspective [2], as well as in terms of particular transmit strategies. In particular, zero-forcing beamforming has been shown to require CSIT quality that scales proportional to SNR [3]=-=[5]-=-. Large systems have been shown to be able to operate near capacity with extremely low-rate channel feedback in the asymptotic limit as the number of users is taken to infinity. In particular, random ... |

28 | Asymptotic capacity of beamforming with limited feedback
- Santipach, Honig
- 2004
(Show Context)
Citation Context ...is information to the transmitter, along with the channel norm ||hk|| 2 . Here, C consists of random unit-vectors independently chosen from the isotropic distribution on the M-dimensional unit sphere =-=[4]-=- (RVQ). Each user is assumed to use a different and independently generated codebook1 . The transmitter uses lowcomplexity greedy user selection [13] along with zero-forcing 1 Note that random vector ... |

23 | Finite-rate feedback MIMO broadcast channels with a large number of users
- Yoo, Jindal, et al.
- 2006
(Show Context)
Citation Context ...lection purposes. We consider only the case when the channel norm information ||hk|| 2 is fed back, as opposed to (the receiver’s estimate of) the SINR, which may take quantization error into account =-=[14]-=-. The parameter B is varied within 1 + log 2 M ≤ B ≤ T M . In general, if RZF-RVQ(P, M, K, B) represents the ZF rate for a system with M antennas at the transmitter, SNR P and K users, each feeding ba... |

22 | On the User Selection for MIMO Broadcast Channels
- Bayesteh, Khandani
- 2008
(Show Context)
Citation Context ... much larger up to the point where essentially near-perfect CSIT (relative to the system SNR) is achieved (e.g., 25 bits when M = 4 and the system is at 10 dB). II. PRIOR WORK Previous work [8][9][10]=-=[11]-=- has studied situations where the individual receivers determine whether or not to feedback on the basis of their current channel conditions (i.e., channel norm and quantization error). If each receiv... |

17 |
Wigger,“On the capacity of a MIMO fading broadcast channel with imperfect transmitter side-information
- Lapidoth, Shamai, et al.
- 2006
(Show Context)
Citation Context ... • • Finite systems have been shown to be extremely sensitive to the accuracy of the CSIT, and thus require highrate feedback. This has been shown from a fundamental information theoretic perspective =-=[2]-=-, as well as in terms of particular transmit strategies. In particular, zero-forcing beamforming has been shown to require CSIT quality that scales proportional to SNR [3][5]. Large systems have been ... |

16 |
MIMO broadcast scheduling with quantized channel state information
- Swannack, Womell, et al.
- 2006
(Show Context)
Citation Context ...back is much larger up to the point where essentially near-perfect CSIT (relative to the system SNR) is achieved (e.g., 25 bits when M = 4 and the system is at 10 dB). II. PRIOR WORK Previous work [8]=-=[9]-=-[10][11] has studied situations where the individual receivers determine whether or not to feedback on the basis of their current channel conditions (i.e., channel norm and quantization error). If eac... |

13 |
A two-stage approach to feedback design in multi-user MIMO channels with limited channel state information
- Zakhour, Gesbert
- 2007
(Show Context)
Citation Context ... compare against channeldependent approaches in the future. Another recent work has studied the tradeoff between multiuser diversity and accurate channel feedback in the context of two-stage feedback =-=[12]-=-. In the first stage, all users feed back coarse estimates of their channel, based on which the transmitter runs a selection algorithm to select M users who feedback more accurate channel quantization... |

12 | Jr., “Performance of orthogonal beamforming for SDMA with limited feedback
- Huang, Andrews, et al.
- 2009
(Show Context)
Citation Context ...eedback is much larger up to the point where essentially near-perfect CSIT (relative to the system SNR) is achieved (e.g., 25 bits when M = 4 and the system is at 10 dB). II. PRIOR WORK Previous work =-=[8]-=-[9][10][11] has studied situations where the individual receivers determine whether or not to feedback on the basis of their current channel conditions (i.e., channel norm and quantization error). If ... |

7 | Fundamental limits in MIMO broadcast channels
- Hassibi, Sharif
- 2007
(Show Context)
Citation Context ...om beamforming throughput to perfect CSIT capacity converge to one as the number of users is taken to infinity, but the difference between these quantities actually has been shown to converge to zero =-=[7]-=-. Finite systems require high-rate feedback because imperfect CSIT leads to multi-user interference that cannot be resolved at each receiver. In order to prevent such a system from becoming interferen... |

7 | Scalable feedback protocol for achieving sum-capacity of the MIMO BC with finite feedback,” Stanford
- Agarwal, Hwang, et al.
- 2006
(Show Context)
Citation Context ...k is much larger up to the point where essentially near-perfect CSIT (relative to the system SNR) is achieved (e.g., 25 bits when M = 4 and the system is at 10 dB). II. PRIOR WORK Previous work [8][9]=-=[10]-=-[11] has studied situations where the individual receivers determine whether or not to feedback on the basis of their current channel conditions (i.e., channel norm and quantization error). If each re... |