Abstract:
Disclosed are the design and implementation of a CSI feedback channel in a multi-carrier wireless communication system. An apparatus and a method for channel state feedback using arithmetic coding are provided to ensure efficiency and reliability of a system by transmitting the CSI while compressing the CSI with a predetermined compression rate selected depending on a channel state. The apparatus for CSI feedback in a wireless communication system performing channel estimation at a transmitter or a receiver by using a communication channel includes a transmitter terminal transmitting a signal for CSI measurement by using the communication channel, and a receiver terminal receiving the signal from the transmitter terminal, checking a channel state based on the received signal, and transmitting the signal to the transmitter terminal after compressing the signal according to the channel state.
Abstract:
A system for variable bit-rate video coding in which encoding bandwidth as characterized by a usage parameter control (UPC) parameters is renegotiated between a video encoder and an asynchronous transfer mode network in order to maintain quality-of-service and save bandwidth. The coding system includes adjusting the video source quantization in a manner for controlling the occupancy level of a buffer while new UPC parameters are requested from an ATM network.
Abstract:
In a communication system serving a plurality of transmitter-receivers, high capacity is achieved by asynchronous contention access of relatively short reservation request packets, which if successfully transmitted result in the scheduled, noncontention transmission of relatively long message data packets. In a first embodiment, the reservation request packets bear information relating to the duration of the message data packets, so that appropriate message data transmission time may be scheduled. Unsuccessful or colliding reservation request packets are retransmitted. In a second embodiment, the reservation requests packets do not include duration information, and the message data packets have fixed duration. In the second embodiment, collision resolution techniques allow the message data scheduling without retransmission of some colliding reservation request packets. It is also possible to operate in both modes, by scheduling random length message data transmissions as a result of noncolliding reservation request packets, and by scheduling fixed duration message data transmissions when reservation request packets collide.
Abstract:
A multimedia communications and computer platform that can serve as a network interface card combined with an internal distribution network for a full range of user terminal devices. It includes an interconnection network module that serves to route all incoming and outgoing information by way of high speed buses with value added features for communication protocol acceleration. In particular, attached to the different ports of the network are an ATM module, a communications processor, a media processor and a variety of terminal devices. By migrating processing intensive functions of network protocol termination, media stream distribution and media stream adaptation into the network interface card, there are avoided the bottlenecks of the traditional CPU centric approach to ATM systems.
Abstract:
An improved time division multiple access (TDMA) satellite transmission system uses N TDMA stations and employs a signal format in which successive time frames begin with a header containing synchronizing and control signals generated by a selected TDMA and followed by N time slots, and in which each TDMA station generates and transmits data packets having a high energy level during a unique time slot assigned to each TDMA and in which each TDMA transmits data packets only during its assigned time slot, and further in which at least some of the TDMA's do not transmit data packets in the available time during the assigned time slot, thereby leaving unpredictably occurring idle time. Apparatus is provided for using a substantial portion of the idle time. The apparatus includes a plurality of random access terminals (RATS) each constructed to generate and transmit a data packet, having a lower energy level then the TDMA energy level, to any given single time slot during each frame and logic apparatus is provided for selecting such given single time slot on a predetermined statistical basis. Each RAT is capable of receiving all successfully transmitted data packets and determines the successful or non-successful transmission of any data packet originating therefrom. Data is retransmitted by the RAT's during a subsequent frame when the originally scheduled RAT transmission is not successfully completed.
Abstract:
The present invention changes the wireless information service paradigm from a connection-oriented unicast network model to a dynamic content-driven multicast model using a technique called “content routing.” The present invention provides a system, method, and medium for routing content through a network from at least one content provider to at least one content consumer, wherein at least one of the content consumer or content provider communicate with the network using a wireless device. The content is routed though the network based on its content. The content is labeled with at least one content descriptor. The content descriptor characterizes or otherwise describes the content. Interest profiles are received from content consumers. Interest profiles from content consumers with a common network access point are aggregated into a single interest profile. Interest profiles can include more than the wireless consumers stated interest, such as for example, a content consumer's geographic location, the capabilities of the wireless terminal, type of service, policy preferences, and the like. Single interest profiles are shared across neighboring network access points to create a content routing table. Content, labeled with at least one descriptor, is routed through the network to content consumers based, in part, on content routing tables created from wireless content consumers'profiles.
Abstract:
Mobility in a wireless ATM network is accomplished by use of hand-off control protocols. A mobile terminal signals a first base station that a hand-off is to occur. In a first preferred embodiment the first base station signals a second base station requesting a hand-off. After the second base station signals the first base station that a datapath link is available from a hand-off switch to the second base station, the hand-off switch causes the datapath to change from the first base station to the second base station and the first base station signals the mobile terminal to commence communication with the second base station. In a second preferred embodiment, the mobile terminal signals a first base station that a hand-off is to occur. The first base station signals a second base station requesting a hand-off. At the same time a datapath link is established between the first and second base stations. When the second base station signals the first base station that the datapath link is available, the first base station signals the mobile terminal to change to the second base station and data is sent from the first base station to the second base station via the available established datapath link.
Abstract:
An asynchronous random access system includes stations which in one embodiment transmit information as packets at random times. After a path delay, all stations receive the packets. By comparing the period of activity at the station with the known packet length, all stations know when a collision occurs. According to the system protocol, all station inhibit new transmissions for a predetermined time which includes a retransmission time. Stations whose packets were involved in the collision know that their transmission was unsuccessful, and they can also determine whether their own packets were first or last in the collision, based upon the known path delay. Retransmission of the first and last packets occurs during the retransmission interval and is guaranteed to be successful, because all other stations are inhibited. In another embodiment, evaluation of the received data is also performed to establish which packets are second and/or penultimate in collision, and they are also retransmitted according to a prescribed schedule.
Abstract:
A handoff control process in a wireless ATM network replaces an old communications connection with a new communication connection. In order to guarantee that no data is lost during the replacement process, an ATM cell level mechanism is used to re-schedule the buffering and transmitting of data streams of the virtual channels (VCs) to be handed-off. In addition, this mechanism is transparent to user applications. The present invention performs three fundamental cell level scheduling functions. The first function is to mark and redirect cell transmission with operation and maintenance (OAM) cells. The second function is to disable and buffer cell transmission until the new path is connected. The third function is to enable cell transmission, starting with the buffered cells across the connected new path.
Abstract:
A data link control procedure for wireless ATM access channels based on a dynamic TDMA/TDD framework provides integrated ATM services including available bit-rate (ABR) data and constant/variable bit-rate (CBR/VBR) voice or video through the addition of wireless-specific medium access control and data link control protocol layers between the physical and ATM network layers. Generally, a data link control is used to insulate the ATM network layer from wireless channel impairments by selective retransmission of erroneous or lost cells before they are released to the ATM layer. The data link control methods disclosed use the on-demand ABR burst transmission capability of the dynamic TDMA channel to retransmit unacknowledged cells in available slots not allocated to service data. Specific error recovery procedures for both (asynchronous) ABR and (isochronous) CBR services are provided.