Improving MU-MIMO performance in LTE-(advanced) by efficiently exploiting feedback resources and through dynamic scheduling

Bhamri, Ankit; Kaltenberger, Florian; Knopp, Raymond; Hämäläinen, Jyri

doi:10.1109/wcnc.2013.6554625

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…In the optimization problem of eqs. (10)- (12) we have now two sets of sub-bands, set K F in which the UEs can employ all the available min{R s , T s } spatial degrees of freedom and the set K A * where only the min{R s − L p k , T s − L p k } ones can be employed by considering the transmission through the equivalent MIMO system whose channel matrix is the J lk one. With the latter transformation the LTE-A system satisfies both the zero interference constraints as it aligns its transmitted signals to orthogonal subspaces to the ones of the PUs at the unlicensed bands.…”

Section: A Problem Formulationmentioning

confidence: 99%

“…Now that the interference constraints are satisfied, we move forward in the derivation of the pre-/post coding matrices S lk , W lk , T lk and B lk of the equivalent optimization problem of eqs. (10)- (12). Let us recall that that in each one of the available RBs the LTE-A system can establish its communication link via a MIMO frequency flat fading channel whose channel matrix is either H lk for licensed RBs and unlicensed RBs with no active PU or the equivalent one J lk for an unlicensed RB with an active PU on it, as described in the previous paragraph.…”

Section: A Problem Formulationmentioning

confidence: 99%

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Resource Allocation for Licensed/Unlicensed Carrier Aggregation MIMO Systems

Tsinos

Foukalas

Tsiftsis

2017

IEEE Trans. Commun.

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Abstract-In this paper a novel Carrier Aggregation (CA) scheme is proposed for downlink MIMO LTE-A Systems. The proposed approach achieves increased transmission rates by establishing the communication links via both licensed and unlicensed bands without generating or experiencing interference to/from the users of the latter bands. To that end, a rate optimization problem is defined and solved subject to the previous zero interference constraints, a total power constraint and a maximum number of aggregated bands constraint. It turns out that the previous problem is a Mixed Integer Non Linear Programming (MINLP) one that requires an exhaustive search procedure in order to be solved. To tackle this, an optimal low complexity method is proposed based on the Lagrange dual decomposition. The performance of the original (MINLP) and the low-complexity proposed techniques is verified via indicative simulations.

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Section: A Problem Formulationmentioning

confidence: 99%

Section: A Problem Formulationmentioning

confidence: 99%

Resource Allocation for Licensed/Unlicensed Carrier Aggregation MIMO Systems

Tsinos

Foukalas

Tsiftsis

2017

IEEE Trans. Commun.

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“…In the system model shown in Fig. 1, the AMC module can not only dynamically adjust modulation and code schemes through channel states information (CSI), but also make use of feedback channel information from the receiver and adopt different judgment criteria to choose the appropriate multiple antenna modes [11]. The judgment criteria based on SNR, channel capacity, minimum BER have been given in references [12]- [14].…”

Section: Antenna Schedulementioning

confidence: 99%

An Enhanced Feasible Adaptive Scheduling Algorithm for 3GPP LTE-Advanced System

Liu¹,

Tan²,

Huang³

et al. 2016

jcm

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-The Third Generation Partnership Project (3GPP) initially defined Release-8 as the first standard of the Long Term Evolution (LTE), a novel high-speed all-IP wireless access technology for mobile communication system using OFDMA and MIMO as native technologies. However, even this high-speed technology was found incapable of meeting true IMT-Advanced 4G requirements. As such, Release-10 Release-11 and Release-12, which is known as LTE-Advanced, was released to achieve this target with further improvements while maintaining backward compatibility with Release-8. The main contribution of this paper is to undergo some thorough research on the key technologies of the adaptive LTE-A system based on 3GPP LTE-A physical layer specifications, and then give the adaptive system performance simulation and analysis. Specifically, in the design scheme of the adaptive LTE-A system, more research about adaptive modulation and coding has been given, which includes a new rate matching algorithm based on circularly selecting and interlaced puncturing as well as a different antenna mechanism based on adaptive scheduling solution in order to enhance the system performance. Simulation results indicate that the system with the improved adaptive schemes has better performance which could also prove the design of the adaptive system is accurate and reasonable.

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