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 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.
Abstract:
A medium access control (MAC) layer protocol is used in a wireless ATM system for integrated support of ATM services, including constant bit-rate (CBR), variable bit-rate (VBR) and available bit-rate (ABR) services. The MAC protocol supports both connectionless packet and connection-oriented virtual circuit modes, with appropriate service parameter and quality-of-services selection. A dynamic time division, multiple access/time division multiplex (TDMA/TDM) approach accommodates the service classes in an integrated manner. A supervisory MAC procedure integrates ATM ABR/VBR/CBR virtual circuits, providing burst-by-burst allocation of ABR cells and call-by-call allocation of VBR and CBR bandwidth parameters. A mechanism is provided for the dynamic allocation of subframe capacities, assignment of ABR slots based on desired queueing rules, assignment of VBR slots based on ATM traffic shaper parameters and assignment of CBR slots based on bandwidth requirements.
Abstract:
A transmission system employing a satellite and a plurality of ground stations each capable of transmitting and receiving data packets to and from each other via the satellite. The satellite station comprises first logic for dividing absolute time into time frames and time frames into message (time) slots with each message slot having a small percentage thereof divided into mini-slots and with each mini-slot in each message slot corresponding to a particular message slot in a future time frame, and second logic including a random number selector responsive to the selection of message slots in the same current time frame by two or more data packets, and third logic for randomly selecting mini-slot for each message slot in which a data packet is to be transmitted in the current time frame with the selected mini-slot for each message slot in the current time frame defining the particular message slot in the future time frame in which the data packet is to be transmitted in case two stations select the same message slot in the current time frame to cause a conflict. A future frame is a time frame which occurs after the data packet in the current time frame has propagated from its originating ground station to the satellite and then back to the originating ground station.
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.