Tellabs Oy

Abb Industry Oy

Coriant Oy

Janne Väänänen

Mikko Laulainen

Heikki Laamanen

Olli Pyrhonen

Marko Kulmala

The invention relates to a method and equipment for performing flow shaping that maintains service quality in packet-switched telecommunications. Using the method according to the invention, the speed properties (OR, PIR, CBS) of an aggregate flow (A) can be monitored and limited in a situation, in which the aggregate flow contains delay-critical traffic (V), the forwarding of packets representing which cannot be delayed. The invention is based on the fact that, when forwarding packets representing the aggregate flow, a variable is updated, the value of which expresses the earliest permitted moment, at which a packet, representing traffic (V) other than the delay-critical traffic, can be forwarded. In that case, the transfer speed of the traffic (V) other than delay-critical traffic adapts to the variations in the transfer speed of the delay-critical traffic, allowing the speed properties of the aggregate flow to be monitored and limited.

Method and equipment for performing flow shaping that maintains service quality in packet-switched telecommunications

The invention relates to a method and equipment for performing aggregate-portion-specific flow shaping in packet-switched telecommunications, in such a way that the traffic flows (V-VL) arriving in the system can be arbitrarily bundled into shaping groups and the speed properties (CIR, PIR, CBS) of an aggregate portion formed of packets representing the arbitrary shaping group (k) can be monitored and limited (aggregate-portion-specific shaping group). The invention is based on the fact that the earliest permitted moment, at which a packet in the system can be forwarded, is defined as the greatest value of the VTS values of all the shaping groups to which the traffic flow represented by the packet belongs, and as a result of the forwarding of the packet, the VTS values of the same shaping groups (k) are updated, in which the VTS value of an individual shaping group (k) expresses the earliest permitted moment, at which a packet belonging under the relevant shaping group (k) can be forwarded, without breaking the restrictions of the speed properties of the shaping group (k) being examined.

Method and equipment for performing aggregate-portion-specific flow shaping in packet-switched telecommunications

The invention relates to a method and apparatus for scheduling transmission-link capacity between packet switched telecommunications flows (L, L), in such a way that it is possible to ensure the scheduling of packets representing delay-critical traffic to the transmission link (S) before packets representing non-delay-critical traffic and, in addition, to achieve the desired division of the capacity of the transmission link (S) between different traffic groups. The invention is based on performing the selection in the scheduling in stages, as follows: 1) the packets with the highest priority among the packets being offered are sought and 2) from the sub-group obtained, a final selection is performed using a weighting-factor based scheduling method, in such a way that the same weighting-factor based scheduling process is used to handle the sub-groups representing different priority levels in the consecutive selection situations.

Method preserving delay properties and an apparatus for scheduling transmission link capacity between packet switched telecommunications flows

The invention relates to a method and apparatus for scheduling transmission-link capacity between packet-switched telecommunications flows, in such a way that it is possible to guarantee that packets representing delay-critical traffic will be scheduled to the transmission link (S) before packets representing non-delay-critical traffic and, in addition, that it is possible to limit the joint transmission speed of specific service-quality classes of an individual customer flow. The invention is based on the service-quality classes being separated into two different categories: a service-quality-class based scheduling branch (C) and a customer-flow based scheduling branch (F). When selecting the next packet to be forwarded, one of the two said branches (C or F) is selected and in the service-quality-class based scheduling branch a service-quality class (CoS) is selected and, within the selected service-quality class, a customer flow (CF) is selected and in the customer-flow based scheduling branch a customer flow (CF) is selected and, within the selected customer flow, a service-quality class (CoS) is selected.

Combined customer-flow and quality-class-based scheduling method and apparatus for scheduling transmission-link capacity between packet-switched traffic flows

The invention relates to a method and equipment for controlling the congestion management and transmission-link-capacity scheduling in packet-switched telecommunications, in such a way that 1) it is possible to define what share of the capacity of the transmission link will be reserved for traffic representing a specific service level class, and 2) it is possible to define the weighting coefficient that the portion of the traffic exceeding the reservation of each service level class will use to compete for the portion of the capacity of the transmission link that is not reserved, or that is reserved but is not being used momentarily by traffic entitled to the reservation, and 3) it is possible to use overbooking, in such a way that the reduction in service quality due to overbooking affects only the service level class in which overbooking is used, and 4) it is possible to prevent an increase in delays detrimental to traffic-flow control even in a congestion situation arising from overbooking. The invention is based on measuring the traffic flow that comes to be scheduled, in which the flow is formed of packets representing a specific service level class arriving in the queue, or some of the relevant packets, and on controlling the operation of the scheduler and congestion limitation mechanism on the basis of the measurement results.

Method and equipment for controlling the congestion management and scheduling of transmission-link capacity in packet-switched telecommunications

The present invention concerns adjustment of tap coefficients of a Tomlinson-Harashima precoder in a digital communications path during a data transmission state. According to the invention, the tap coefficients of the Tomlinson-Harashima precoder are adjusted based on content values of a delay line of the Tomlinson-Harashima precoder and on an error variable associated with a receive. Synchronization between the error value and the content values of the delay line is performed according to line frame synchronization information.

Method and apparatus for implementing a channel correction in a digital data link

The invention relates to a method and apparatus for scheduling transmission link bandwidth between packet-switched data flows so that a desired CoS (Class of Service) is provided with an ability to utilize the instantaneously available bandwidth of a data transmission network while simultaneously offering a guaranteed minimum data rate (Guaranteed Data Rate and Best Effort) without compromising the operation of such classes that have no guaranteed lower bound of data rate, but instead, have the service implemented by the utilization of the instantaneously available bandwidth (Best Effort). The invention is based utilizing in the scheduler control, not only the information indicating the class of service, but also the information indicating the subgroup inside a class of service (e.g., drop precedence). The information indicating the subgroup is conventionally utilized only for congestion control purposes.

Method and apparatus for scheduling available link bandwidth between packet-switched data flows

The invention relates to a method and apparatus for improving the quality of receiver synchronization on QAM- or CAP-modulated modem connections having an adaptive linear equalizer. The invention is based on the finding that in a QAM- or CAP-modulated data transmission system where the symbol rate and the average carrier frequency are in fixed relationship with each other, the vector formed by the In-phase and the Quadrature component of the detector input signal rotates with the timing phase shift of the receiver. The quality of receiver synchronization is improved by utilizing information extracted from the vector rotation.

Method and apparatus for increasing the quality of the receiver synchronization of QAM or CAP modulated modem connection

The invention relates to implementing a training phase of adaptive channel equalization on a digital communications path using QAM- or CAP-modulation method and comprising at least one band-stop filter that forms a stop band on a the signal spectrum. Training of adaptive equalizers is performed utilizing a sparse symbol constellation, wherein a number of symbol states (S) is smaller than that of a symbol constellation used in a normal data transmission state. The benefit of the sparse symbol constellation is that a strong intersymbol interference caused by the stop band can thus be reduced to such a low level in regard to a signal power that a linear equalizer may be used to reach a situation, wherein a proportion of correct symbol decisions becomes sufficiently high for training of a decision-feedback equalizer.

Method and system for training adaptive channel equalization

A method and an arrangement are provided for synchronizing a receiver into a quadrature amplitude modulated (QAM) signal. The receiver comprises a first controllable unit () arranged to respond to a timing control signal by controlling the timing by which a received signal is converted into demodulated complex samples. Additionally it comprises a symbol detector () arranged to produce, in correspondence with the complex samples, a detection decision (s) that represents a received symbol. There are elements () for generating one or more complex baseband equivalent impulse response values for a QAM-channel as a correlation result by correlating complex demodulated samples with a complex correlation variable (C) derived from the detection decision (s). The sensitivity to changes caused by cables rotating the baseband equivalent impulse response and by the unknown phase difference between the transmitter upmodulator and the receiver demodulator is deleted by appropriate postprocessing of the correlation results. The timing control signal is derived from the postprocessed correlation results.

Method and arrangement for synchronizing a receiver to a quadrature amplitude modulated signal

The invention relates to a method of ensuring the stability of a synchronous machine in controlling the synchronous machine on the basis of direct control of flux and torque, in which the torque generated by the synchronous machine is increased/decreased by increasing/decreasing the instantaneous angular velocity of the stator flux. In accordance with the invention, the method comprises the steps of determining the direction of the stator flux vector (.psi.s) in rotor coordinates (dq), and forcing the stator flux vector (.psi.s) to remain in quadrants I and IV (Q1, Q4) of the rotor coordinates by rotating the stator flux in the rotor coordinates to a necessary degree.

Growing community of inventors

Espoo, Finland

Janne Väänänen