Opportunistic interference management: a new approach for multiantenna downlink cellular networks

Abstract

A new approach for multiantenna broadcast channels in cellular networks based on multiuser diversity concept is introduced. The technique called opportunistic interference management achieves dirty paper coding capacity asymptotically with minimum feedback required. When there are K antennas at the base station with M mobile users in the cell, the proposed technique only requires K integer numbers related to channel state information between mobile users and base station. The encoding and decoding complexity of this scheme is the same as that of point‐to‐point communications, which makes the implementation of this technique easy. An antenna selection scheme is proposed at the base station to reduce the minimum required mobile users significantly at the expense of reasonable increase in feedback. In order to guarantee fairness, a new algorithm is presented that incorporates opportunistic interference management into existing Global System for Mobile communications (GSM) standard. Copyright © 2014 John Wiley & Sons, Ltd.

Taking advantage of multi-user diversity in OFDM systems

“…Details of how to formulate the conditional distribution of d given a certain number of MS antennas n can be found in the appendix. Then, the expected multiplexing gain D = E d is found using Theorem 1 in [8]. Therefore, Figure 1.…”

“…The theoretical plot of D using (9) and the plot of the channel simulation can be seen to be approximately the same. Therefore, for any given number of BS and MS antennas, OIM conditions, and sub-channel group size, we can determine what the expected multiplexing gain is for the system using equations (6,7,8,9). Note that in the original OIM without OFDM, we require more than 30000 nodes to achieve multiplexing gain of two, while by using OFDM, we need less than 1500 nodes to achieve the same multiplexing gain.…”

“…Due to this high correlation between sub-channels, if a mobile station (MS) antenna satisfies the OIM condition, there is a high probability that the MS antenna satisfies the OIM condition in the neighboring sub-channels. In order to apply the OIM technique [8] to OFDM systems efficiently, we consider groups of sub-channels, and only transmit using the OIM technique if a MS antenna satisfies the OIM condition with the same BS antennas for the entire group of sub-channels. Hence, in each group, we can transmit data from a set of BS antennas to a set of MS antennas within the same group of sub-channels, so long as each BS antenna sends data to only one MS antenna, and each selected MS antenna receives data from only one BS antenna.…”

“…Hence, in each group, we can transmit data from a set of BS antennas to a set of MS antennas within the same group of sub-channels, so long as each BS antenna sends data to only one MS antenna, and each selected MS antenna receives data from only one BS antenna. As in the original OIM technique [8], the expected value of the multiplexing gain D = E d is computed analytically and compared to simulation results.…”

Taking advantage of multiuser diversity and beamforming in wireless cellular networks

“…By setting threshold conditions for strong and weak channels, this requirement leads to the SINR of each user sending feedback to be above a certain threshold, hence guaranteeing a threshold achievable rate performance. This technique is also shown to asymptotically approaches DPC [9] performance.…”