Abstract:
Methods and apparatus for piecewise linear neuron modeling and implementing artificial neurons in an artificial nervous system based on linearized neuron models. One example method for operating an artificial neuron generally includes determining that a first state of the artificial neuron is within a first region; determining a second state of the artificial neuron based at least in part on a first set of linear equations, wherein the first set of linear equations is based at least in part on a first set of parameters corresponding to the first region; determining that the second state of the artificial neuron is within a second region; and determining a third state of the artificial neuron based at least in part on a second set of linear equations, wherein the second set of linear equations is based at least in part on a second set of parameters corresponding to the second region.
Abstract:
In a high data rate communication system, a method and apparatus for improved throughput while transmitting data packets within multiple time slots. In order to avoid unnecessary retransmissions of a packet, a subscriber station sends a Stop-Repeat signal to a base station, causing the base station to cease further transmissions of the packet. In order to enable successful decoding of a packet, a subscriber station sends a Continue-Repeat signal to a base station, causing the base station to send retransmissions of the packet during time slots beyond a predetermined default number of time slots.
Abstract:
In a CDMA data communication system capable of variable rate transmission, utilization of beam switching techniques decreases the average interference caused by transmissions of a base station to subscriber stations within a cell, and in neighboring cells. Base stations utilize multiple transmit antennas, each transmitting signals at controlled amplitudes and phases, to form transmit signal corresponding to sector divisions. Data and reference signals are transmitted along sector division beams that alternate according to fixed time slots in order to increase system capacity and data rates by maximizing carrier-to-interference ratios (C/I) measured at subscriber stations.
Abstract:
In a data communication system capable of variable rate transmission, high rate packet data transmission improves utilization of the forward link and decreases the transmission delay. Data transmission on the forward link is time multiplexed and the base station transmits at the highest data rate supported by the forward link at each time slot to one mobile station. The data rate is determined by the largest C/I measurement of the forward link signals as measured at the mobile station. Upon determination of a data packet received in error, the mobile station transmits a NACK message back to the base station. The NACK message results in retransmission of the data packet received in error. The data packets can be transmitted out of sequence by the use of sequence number to identify each data unit within the data packets.
Abstract:
Techniques to improve the acquisition process in a spread spectrum environment. The signals from different CDMA systems are spread with different sets of PN sequences, with the PN sequences in each set being uncorrelated to the PN sequences in the other sets. By using uncorrelated PN sequences, the likehood of detecting a pilot signal from an undesired system is reduced or minimized, and the mean time to acquisition of the pilot signal from the desired system is improved. The mobile station can attempt to acquire the pilot signal by processing the received signal with a first set of PN sequences corresponding to a first hypothesis of the particular signal being acquired. If acquisition of the pilot signal fails, a second set of PN sequences corresponding to a second hypothesis is selected and used to process the received signal. The PN sequences in the second set are uncorrelated to the PN sequences in the first set. The PN sequences for the first set can be generated based on the characteristic polynomials defined by IS-95-A, and the PN sequences for the second set can be the reverse of the PN sequences for the first set.
Abstract:
A novel and improved system and method for assembling a single data stream from multiple instances of that data stream is described. Data transmitted from a cellular telephone subscriber unit (100) is received by a set of base transceiver stations (102). Each base transceiver station performs various error detection procedures on segments of the data referred to as frames (300). These error detection procedures may include CRC check sum verification, Yamamoto metric calculation, re-encoded signal error rate calculation, or a combination thereof. The results of these error detection procedures are placed into a frame quality metric (308). The frame (200), frame quality metric (308), a time stamp (310) and an address (312) are placed into a packet (305) that is transmitted from each base transceiver station to a mobile telephone switching office (104) which matches packets (305) attempting to transmit the same information using the time stamp and selects one frame (300) from the packets (305) for further processing based on the associated frame quality metric (308).
Abstract:
A power control system for communication systems which utilizes a ternary signaling scheme to reduce or eliminate limit cycling which occurs as the result of using a binary signaling scheme. The power control values (each having one of three possible values) are not encoded and are punctured onto the data to improve the response time of the power control loop and allow for dynamic adjustment of the transmit power. The power up, power down, and do nothing commands are represented by positive, negative and zero values (e.g., +1, -1, and 0), respectively. The remote station (6) decreases its transmit power if any base station issues a power down command, maintains its transmit power if no base stations (4) issue a power down command and at least one base station issues a do nothing command, and increases its transmit power if all base station issue power up commands.
Abstract:
In a data communication system capable of variable rate transmission, high rate packet data transmission improves utilization of the forward link and decreases the transmission delay. Data transmission on the forward link is time multiplexed and the base station transmits at the highest data rate supported by the forward link at each time slot to one mobile station. The data rate is determined by the largest C/I measurement of the forward link signals as measured at the mobile station. Upon determination of a data packet received in error, the mobile station transmits a NACK message back to the base station. The NACK message results in retransmission of the data packet received in error. The data packets can be transmitted out of sequence by the use of sequence number to identify each data unit within the data packets.
Abstract:
A method for assigning optimal packet lengths in a variable rate communication system capable of data transmission at one of a plurality of data rates. The packet lengths for the data rates are selected such that the maximum throughput rate is achieved while conforming to a fairness criteria. The fairness criteria can be achieved by restricting the packet length assigned to each data rate to a range of value, or Limin ≤ L¿i? ≤ Li?max¿. The packet lengths for all data rates are first initialized to the maximum packet lengths for those data rates. Then, for each date rate, a determination is made whether another packet length assignment would result in improved throughput rate. If the answer is yes, the packet length for this data rate is reassigned and the throughput rate with the updates packet length assignments is recomputed. The process is repeated for each data rate until all data rates have been considered. The throughput rate can be calculated using a probabilistic model or a deterministic model.4