Abstract:
Individual RF cables span between element/transceiver pairs in traditional beam forming systems, and the number of elements in an array used for beam forming is thus restricted. To reduce the number of RF cables but maintain or increase the number of elements in an antenna array, an embodiment of the present invention includes electronics at the base of an antenna tower that apply digital multiplexing codes to signals communicated to electronics located at the top of the antenna tower. The electronics at the top demultiplex the signals and transmit them via the antenna array. Received RF signals are processed in a like manner in a reverse direction. Fewer transmission paths (e.g., RF or fiber optic cables) than the number of elements in the antenna array can be used. More antenna elements provide benefits, such as higher user capacity, more antenna beams, narrower antenna beams, and higher in-building penetration.
Abstract:
Data rate allocation decisions are made for a communications channel, such as a wireless reverse link connection. A first parameter used in this determination is a path loss, which is determined by the following process. First, a message is sent from a first station to a second station, such as on a paging channel. The message indicates a forward Effective Radiated Power (ERP) of a pilot signal transmitted by the first station. The second station then determines the received signal strength of this pilot signal, taking into account receiver gains. The path loss can then be estimated by the second station as the difference between the forward ERP data value that it received and the detected received pilot power. The second station also then preferably determines a transmit power level when transmitting a message back to the first station. This transmit power level information is encoded as a digital data word together with the forward path loss information as calculated by the first station. Upon receipt of these two pieces of information by the first station, the forward path loss estimate as calculated by the second station, and the output power value of the second station, the first station can then determine the amount of excess power available at the field unit. This excess power difference is indicative of the amount of dynamic range available in the transmit power amplifier in the particular second station. With this information, the first station can then make a determination as to whether coding rates which require a higher dynamic range will be acceptable for use by the particular second station.
Abstract:
A frequency translating repeater (200) for use in a WLAN environment includes an in-band management link. A signal received on an antenna (300) is split to provide signal detection in a detection and control unit (385) wherein detection is performed by detectors (370, 371) filters (375, 376), converters (380, 381) and a processor (385). Delay is added using delay lines (360, 361). The in-band signal envelope may be modulated with variable gain amplifier (330) and demodulated with detectors (370, 371) to establish the management link with higher protocol layer capability. Alternatively, a modern function at least partially compliant to 802.11 modulation may be used in parallel with the frequency translating repeater.
Abstract:
A repeater (200) facilitates wireless communication between a first communication device (100) and a second communication device (105) in a wireless network using a time division duplex protocol for data transmission. The repeater (200) includes a receiver (310, 315) for receiving a signal on either of at least two bi-directional communication frequencies simultaneously. A signal detector (362) is operatively coupled to the receiver (300, 310, 315) for determining if the signal is present on at least one of the two bi-directional frequencies. A frequency converter (320, 321, 323, 324, 360, 361) is for converting the signal present on one of the bi-directional frequencies to a converted signal on the other of the bi-directional frequencies. A transmitter (300, 325, 330, 335, 345, 350) is for transmitting the converted signal on the other of said bi-directional frequencies.
Abstract:
A packet data system such as a TCP/IP network transmits packets containing a variety of data types along links in the network. Packets are transmitted in a stream between nodes interconnected by the links, which conform to a transport layer protocol such as TCP, UDP, and RSTP, and include wireless links, which transmit packets using a radio frequency (RF) medium. Typical protocols, however, are usually developed to optimize throughput and minimize data error and loss over wired links, and do not lend themselves well to a wireless link. By examining the data in a packet, performance characteristics such as a port number are determined. The performance characteristics indicate the application type, and therefore, the data type, of the packets carried on the connection. Since certain data types, such as streaming audio and video, are more loss tolerant, determination of the data type is used to compute link control parameters for the wireless link that are optimal to the type of data being transmitted over the link.
Abstract:
A system and method for encoding/decoding data channels in a CDMA system having data channel interference cancellation, wherein data channel interference cancellation is used to remove unwanted non-orthogonal pilot signal components which are present within a demodulated data signal. This is accomplished by regenerating interference terms with respect to the non-orthogonal pilot signal and subtracting them from the demodulated data signal.
Abstract:
A varactor based phase shifter that increases phase shift range using a lower characteristic impedance between quadrature ports than is used at its input/output ports. The circuit makes use of a four port coupler arrangement that imbeds a quarter wave impedance transformation between the input port and the quadrature ports as well as between the quadrature ports and the output port. The characteristic impedance across the quadrature ports is therefore less than the characteristic impedance across the input and output ports. In one implementation, reducing a characteristic input/output impedance of 50 to a 20 ohm quadrature port impedance results in a phase shift range increase of more than 50%.
Abstract:
A directive antenna having plural antenna elements is arranged in a parasitic antenna array. Frequency selective components are connected to an active antenna element. Weighting structures are connected to passive antenna elements positioned substantially equidistant from the active antenna element. The active and passive antenna elements are connected by a space-fed power distribution system to produce independently steerable beams having spectrally separated signals.
Abstract:
An antenna apparatus that can increase capacity in a wireless communication system is disclosed. The antenna operates in conjunction with a station and comprises a plurality of antenna elements, each coupled to a respective weight control component to provide a weight to the signal transmitted from (or received by) each element. The weight for each antenna element is adjusted to achieve optimum reception during, for example, an idle mode when a pilot signal is received. The antenna array creates a beam former for signals to be transmitted from the mobile station, and a directional receiving array to more optimally detect and receive signals transmitted from the base station. By directionally receiving and transmitting signals, multipath fading and intercell interference are greatly reduced. The weights are adjusted in a coarse and a fine mode. In the coarse mode all the weight control components are jointly adjusted or changed so that the antenna beam scans through a predetermined sector of a circle until a signal quality metric of the received signal is optimized. The coarse adjustment mode is followed by a fine adjustment mode during which the weights of are independently adjusted to further optimize the signal quality metric.
Abstract:
A method for operating a subscriber unit that communicates with a code division multiple access (CDMA) wireless network is provided. At the subscriber unit, synchronization information is encoded with a CDMA code. The CDMA encoded synchronization information is transmitted from the subscriber unit in discrete repeating intervals. The discrete repeating intervals are separated by other discrete repeating intervals during which the subscriber unit does not transmit synchronization information.