Abstract:
A technique for allowing a first and second group of users to share access to a communication channel such as a wireless radio channel is disclosed. The first group of users can be a group of legacy users such as those that use digital CDMA cellular telephone equipment based on the IS-95 standard. The second group of users can be a group of web surfers that code their transmissions using one of multiple formats. The first group of users can share one modulation structure such as, on a reverse link, using unique phase offsets of a common pseudorandom noise (PN) code. The second group of users can share another modulation structure, but in a manner that is consistent and compatible with the users of the first group. Specifically, the users of the second group may all use the same PN code and code phase offset. Each channel used by the second group of users can be uniquely identified by a corresponding unique orthogonal code.
Abstract:
An antenna apparatus, which can increase capacity in a cellular communication system or Wireless Local Area Network (WLAN), such as an 802.11 network, operates in conjunction with a mobile subscriber unit or client station. At least one antenna element is active and located within multiple passive antenna elements. The passive antenna elements are coupled to selectable impedance components for phase control of re-radiated RF signals. Various techniques for determining the phase of each antenna element are supported to enable the antenna apparatus to direct an antenna beam pattern toward a base station or access point with maximum gain, and, consequently, maximum signal-to-noise ratio. By directionally receiving and transmitting signals, multipath fading is greatly reduced as well as intercell interference.
Abstract:
A service option overlay for a CDMA wireless communication in which multiple allocatable subchannels are defined on a reverse link by assigning different code phases of a given long pseudonoise (PN) code to each subchannel. The instantaneous bandwidth needs of each on-line subscriber unit are then met by dynamically allocating additional channel capacity on an as needed basis for each network layer connection. The system efficiently provides a relatively large number of virtual physical connections between the subscriber units and the base stations on the reverse link for extended idle periods such as when computers connected to the subscriber units are powered on, but not presently actively sending or receiving data. These maintenance subchannels permit the base station and the subscriber units to remain in phase and time synchronizm by monitoring power, carrier-to-interference (C/I), or signal-to-noise (SNR) ratios. The power levels over the subchannels is regulated to minimize interference. This in turn allows fast acquisition of additional capacity as needed by allocating additional orthogonal codes within the same code phase and by varying the spreading factor of the codes, as well as by adding additional code phases.
Abstract:
A wireless communication node, such as a repeater, including a frequency translating repeater, a physical layer (PHY) repeater, time divisional duplex repeater (TDD) and the like, is configured with a pair of directional patch antennae and an omni-directional antenna. The patch antennae can be selected depending on the orientation of the repeater package to communicate with a station such as an access point or a base station. The omni-directional antenna can be directed toward another station such as a client. The patch antennae and the omni-directional antenna can be orthogonally polarized to increase isolation and reduce electromagnetic coupling. Multiple antennae can be used in multiple-input-multiple-output (MIMO) configurations.
Abstract:
A technique for steering a directional antenna such as may be used with User Equipment (UE) in a wireless communication system. Optimum angle settings for the directional antenna are determined as different values for an uplink and downlink; that is for simple reception and simple transmission. Thus, rather than determine compromised directions that are picked in an attempt to optimize transmission and reception with the same directional setting, directional settings may be optimized independently. The invention is of particular use in a Time Division Duplex (TDD) system where transmit and receive functions can be operating independently at different times. In further aspects, an optimum direction is determined by estimating an interference signal power which is detected from signals emanating from adjacent base stations (access points) and determining a directional setting that minimizes interference to adjacent cells based upon such measurements. A further level of sophistication in antenna angle setting, is to monitor the loading of adjacent cell sites base stations and turning interference and determine the settings accordingly to minimize interference to such heavily loaded neighbors. Further aspects of the invention adapts to acquisition modes that accommodate the directional setting in active use of the system.
Abstract:
A single, common correlation filter (CF) core is provided in a wireless system using CDMA. A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1, tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by digital signal processor (DSP). A user-unique code, such as a PN code, is applied to the information being transmitted in the channels of the wireless system. The information is QPSK modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the smallest data rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code to the correlation filter core. The correlated information is then demultiplexed and pilot aided QPSK demodulated. The demodulated information is summed at the proper integer multiple of the tier 1 rate to achieve the tier 2 and tier 3 rates. The three strongest multipaths (in terms of the received power) are selected in a window or time period for optimal information recovery. Furthermore, three outputs from the demodulated information can be provided and combined for temporal diversity. Spatial diversity is achieved by providing a plurality of antennas at each receiver and a single, common correlation filter at each of the plurality of antennas of the receivers in the wireless system.
Abstract:
A non-frequency translating repeater (110, 210, 300) for use in a time division duplex (TDD) radio protocol communications system includes detection retransmission and automatic gain control. Detection is performed by detectors (309, 310) and a processor (313). Detection can be overridden by processor (313) using logic elements (314). Antennae (220, 230) having various form factors can be used to couple a base station (222) to a subscriber terminal (232) which can be located in a sub-optimal location such as deep inside a building or the like.
Abstract:
Codes are applied to signals to reduce the number of transceivers and associated RF cabling extending from base electronics to antenna array electronics in a base station providing beam forming. The transceivers can be reduced to as few as one, and the RF cabling can be reduced to none. The codes may be orthogonal codes, such as Walsh codes. The codes are applied: to weights used to produce the beam forming, signal being transmitted or received, or both. The codes are applied a second time to decompose the coded weights/signal to associate the weights and signal with the beam forming. The coded weights/signal can be summed, including with other coded weights/signals, to produce a composite code division multiplexed signal for transmission between transceiver(s) and antenna array electronics over a single RF or non-RF cable spanning between the base electronics and array electronics. The complexity, size, and cost of electronics and cables are reduced, and calibration of transceivers and demodulators can be eliminated.
Abstract:
An antenna apparatus, which can increase capacity in a cellular communication system or Wireless Local Area Network (WLAN), such as an 802.11 network, operates in conjunction with a mobile subscriber unit or client station. At least one antenna element is active and located within multiple passive antenna elements. The passive antenna elements are coupled to selectable impedance components for phase control of re-radiated RF signals. Various techniques for determining the phase of each antenna element are supported to enable the antenna apparatus to direct an antenna beam pattern toward a base station or access point with maximum gain, and, consequently, maximum signal-to-noise ratio. By directionally receiving and transmitting signals, multipath fading is greatly reduced as well as intercell interference.