At+t Corp.

At&t Intellectual Property I, L.p.

Other

Justin Che-I Chuang

Xiaoxin Qiu

Kapil K Chawla

Li Fung Chang

Kin K Leung

Li-Chun Wang

Bruce E McNair

Nelson Ray Sollenberger

Amy Ruth Reibman

Gustavo De Los Reyes

Shih-Fu Chang

The invention provides a system that implements an algorithm for integrated link adaptation and power control to achieve specified error rates and to improve an overall throughput for real-time applications in wireless packet networks. The system initially divides wireless terminals into groups according to their signal path gains. Afterwards, the system can periodically adapt transmissions (i.e., link adaptations) based on the required error rates, actual error statistics and average transmission power for each wireless terminal group. Furthermore, transmission power can be adjusted by an enhanced Kalman-filter method to ensure successful reception.

Method and system for integrated link adaptation and power control to improve error and throughput performance in wireless packet networks

A wireless network includes transmission power and data rate adaptation based upon quality experienced by the user.

Wireless network having joint power and data rate adaptation

The present invention implements a method and system for dynamically adapting the modulation and coding scheme for radio links in a wireless communications network based on a retransmission environment model in order to maximize throughput and most efficiently allocate bandwidth resources. The present invention encompasses a refined calculus and methodology for deriving the link adaptation thresholds in a retransmission environment using a complex model and analysis of the retransmission environment. The present invention holds particular application for wireless data communications as opposed to real time data services because it is based on a retransmission model applicable primarily for data services. A critical component of this new link adaptation system is a 'no transmission' cutoff mode that is selected for SIR below a base threshold value. This new mode prevents system instability and misallocation of bandwidth in a wireless communication system.

Link adaptation in wireless networks for throughput maximization under retransmissions

This invention provides interference predictions, suitable for least interference dynamic channel assignment use or other frequency hopping uses by de-coupling the time slot assignment and the frequency hopping pattern assignment. In particular, a least interfered time slot is selected based on an aggregate interference measurement performed across an entire transmission band or a pre-specified range of frequencies in the transmission band. A user is assigned a least interfered time slot and provided an appropriate frequency hopping pattern.

Dynamic channel assignment

A wireless network includes transmission power and data rate adaptation based upon signal quality experienced by the user.

The present invention implements a method and system for dynamically adapting the modulation and coding scheme for radio links in a wireless communications network based on a retransmission environment model in order to maximize throughput and most efficiently allocate bandwidth resources. The present invention encompasses a refined calculus and methodology for deriving the link adaptation thresholds in a retransmission environment using a complex model and analysis of the retransmission environment. The present invention holds particular application for wireless data communications as opposed to real time data services because it is based on a retransmission model applicable primarily for data services. A critical component of this new link adaptation system is a &ldquo;no transmission&rdquo; cutoff mode that is selected for SIR below a base threshold value. This new mode prevents system instability and misallocation of bandwidth in a wireless communication system.

This invention provides wireless resource allocation techniques where the wireless network resource allocation is based on maximum system gain. System gain may be the difference between a maximum performance (e.g., throughput rate) for a requested link and a performance loss of all currently active links affected by the requested link. A currently active link is affected if the requested link is within its link neighborhood. Wireless network resources are allocated to optimize system performance. Inter-base communication may be used to facilitate information exchange among base stations to optimize system performance. The performance loss experienced by any currently active link is called damage to that link. Damage may be determined in a pair-wise fashion based on a nominal performance which may be defined as the performance of a link if interference is experienced only from links which are outside the link neighborhood of the link or as a system parameter. The damage is the difference between the nominal performance and the performance for the link if experiencing interference only from the requested link. Determining damage is computationally efficient because it only requires consideration of the nominal performance and the performance of the requested link. Link neighborhoods limit inter-base station communications and reduces base station interconnect costs.

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Holmdel, NJ, United States of America

Justin Che-I Chuang