A process for recovering a hydrocarbon from a hydrocarbon bearing sand comprising the steps of mixing a chemical additive with a chemical composition and with a hydrocarbon bearing sand containing hydrocarbon and residual solids including clay, at a temperature to form a slurry. The chemical composition comprises an aqueous phase and a minor amount of a chemical agent selected from the group consisting of at least one ethoxylated alkylphenol compound, at least one ethoxylated dialkylphenol compound, MIBC, SC-177, Petronate HL, Clacium Lignosulfonate and mixtures thereof. The slurry is aerated to produce essentially sludge-free tailings and a mixture of hydrocarbon, aqueous phase and residual solids including clay. The process further comprises the step of separating the mixture of the hydrocarbon, the aqueous phase and the residual solids including clay from the essentially sludge-free tailings.

Process for recovery of hydrocarbons and rejection of sand

A message communication system employing one or more centralized communication stations transferring messages through Earth orbit repeater satellites to or from mobile terminals with at least one central communication station having a first transceiver for transmitting a first communication signal to one or more mobile terminals and at least one mobile terminal having a second transceiver for receiving the first communication signal and demodulating it, and for transmitting at a predetermined duty cycle of the second transceiver, a second communication signal to at least one of the central communication stations. The preferred duty cycle over which the second communication signal is transmitted is about fifty percent of the second transceiver duty cycle. The communication system uses Time Division Multiplexed (TDM) communication signals using a number of channels as designated address channels with the remainder being used for data transfer. Information transmitted on the address channels is used by terminals to determine both the presence of a message and its corresponding data transmission or reception channel. In addition the terminals use the reception of the first communication signal to adjust return link transmission frequency to compensate for transmission path errors. The alternating duty cycle allows mobile terminals to use a single set of local oscillators for both transmission and reception modes of operation. To decrease interference with other systems the present system employs a power dispersal modulation function to achieve the footprint of a video signal for high transfer rate digital communication signals.

Alternating sequential half duplex communication system

A wireless PBX system provides ease of installation without site engineering or trial-and-error placement of components within the system. In its basic form, the wireless PBX system consists of only two types of components: a control unit including an radio frequency transceiver; and fixed location terminals, such as telephones and voice/data stations, which also include radio frequency transceivers. Portable handsets are optionally included in the system to allow for customer mobility. Installation of the PBX system is achieved simply by placing the system components in the desired locations at a premises, plugging them into line power, and performing some simple programming steps including a final step of initiating an automatic configuring process. Through this process, the system automatically configures itself for optimum operation in view of the radio environment and placement of components within the system at the customer premises. In the operation of this process, the control unit exchanges various radio messages with the terminals, decides which terminals should also serve as repeaters for linking those more distantly located terminals, and determines the appropriate frame structure for the system. A positive display indication at the control unit, following the end of the automatic configuring process, shows that all terminals have been linked and that the system is operating normally.

Automatically configuring wireless PBX system

The present invention is a communication system and method having a base station for communication with multiple remote units. The system comprises a base station which utilizes a plurality of sets of frequencies for selectively communicating with remote units in a predefined coverage area. The coverage area is divided into N concentric regions, where each concentric region is assigned one of the plurality of frequency sets such that for any given concentric region a different frequency set is assigned than the frequency sets assigned to all other adjacent concentric regions. The base station includes a means for communicating data to a remote unit over the set of frequencies associated with the respective concentric region as the remote unit travels from one concentric region to another. The system also comprises at least one remote unit having means for communicating with the base station over the set of frequencies associated with the respective concentric region as the remote unit travels from one concentric region to another.

Frequency hopping code division multiple access system and method

A new type of data transport service which uses a frame relay layer 2 data link connection identifier (DLCI) to select among various service types, feature sets, and/or closed user groups (CUGs). A layer 3 address may be extracted from a layer 2 frame, and the layer 3 address information may be used to route a data packet over a packet-switched network according to the service classes, feature sets, and/or CUGs selected. At the destination, the layer 3 data packet may again be enclosed in a layer 2 frame with a DLCI indicating the service classes, features sets, and/or CUGs. Because the use of conventional permanent virtual circuits (PVCs) is not required in aspects of the invention, new methods of measuring and managing network traffic are presented.

Frame relay switched data service

A baseband signal switching arrangement for diversity reception in a PCM communication system is disclosed. The switching arrangement is characterized by the provision of a 1/n write-in frequency-dividing counter in each receiving channel to count clock signals in response to being reset by a frame signal and n buffer memory circuits for successively writing bit information of a received digital signal in response to the n frequency-divided outputs of the 1/n frequency-dividing counter. The switching arrangement further includes a 1/n read-out frequency-dividing counter which is adapted to successively read out memory outputs of one set of the n buffer memory circuits and a switching means for enabling the 1/n read-out frequency-dividing counter to selectively read out memory outputs of a given set of buffer memory circuits.

Baseband signal switching arrangement for diversity reception in a PCM radio communication system

@ The apparatus (36) is for a central station in a multi-direction time division multiplex communication system in which the central station transmits signals assigned to respective satellite stations in a time division multiplex broadcast mode, while each of the satellite stations after extraction of a clock extracts the signal assigned thereto and intermittently transmits signals to the central station after adjusting the signals to such a timing that, when the signals reach the central station, the signals from the various satellite stations do not overlap and appear in order as a single sequence of time division multiplex signals. The received signals demodulated by a demodulator (30) are applied to a plurality of code regenerations (32 1 -32 n ) receiving different phase clocks from a clock phase delay circuit (461. A phase comparator (40) compares the phases of the central station clock with a clock extracted (44) from the demodulated signal. A sample and hold circuit (42) holds the output of the phase comparator (40) TDM burst by TDM burst and controls a selector (48) which despite any fluctuation of absolute delay time which may occur during communication between the central and satellite stations due to variations in the ambient conditions, the central station selects the output of that particular code regenerator circuit (32 1 -32 n ) which is operating responsive to a decision clock whose timing matches with the fluctuation, thereby allowing the system as a whole to hold a communication without having the error rate increased. Temporary stores (38 1 -38n) provide delay compensating for the response time of the loop controlling the selector (481.

Multi-direction time division multiplex communication apparatus

A radio communications system has a node station centrally located in a covering area and a plurality of remote substations. The system comprises a plurality of transceivers in the node station, and a plurality of substation transceivers respectively located in the substations corresponding respectively to the node station transceivers to establish a plurality of pairs of two-way radio links therebetween. The covering area is divided into a plurality of concentric zones, each of the zones being assigned a pair of particular frequencies or a pair of particular polarization planes. Each zone has one or more substations. Transmission power level of each of the node station transceivers and each of the substation transceivers is adjusted so that fine-weather reception field strength at each end of those radio links having a greater length is greater than fine-weather reception field strength at each end of those radio links having a smaller length, there being a linear relationship between the field stength at each end of each radio link and the length thereof. The minimum azimuth angular spacing between adjacent substations can be reduced by a factor of 1/4 to allow a greater number of substations to be accommodated in the system.

Radio communications system with reduced D/U ratio variations

A radio communications system has a node station centrally located in a covering area and a plurality of remote substations The system comprises a plurality of transceivers in the node station, and a plurality of substation transceivers respectively located in the substations corresponding respectively to the node station transceivers to establish a plurality of pairs of two-way radio links therebetween The covering area is divided into a plurality of concentric zones, each of the zones being assigned a pair of particular frequencies or a pair of particular polarization planes Each zone has one or more substations Transmission power level of each of the node station transceivers and each of the substation transceivers is adjusted so that fine-weather reception field strength at each end of those radio links having a greater length is greater than fine-weather reception field strength at each end of those radio links having a smaller length, there being a linear relationship between the field strength at each end of each radio link and the length thereof The minimum azimuth angular spacing between adjacent substations can be reduced by a factor of 1/4 to allow a greater number of substations to be accommodated in the system

Radio communications system with reduced interference.

A radio communications system has a node station centrally located in a covering area and a plurality of remote substations. The system comprises a plurality of transceivers in the node station, and a plurality of substation transceivers respectively located in the substations corresponding respectively to the node station transceivers to establish a plurality of pairs of two-way radio links therebetween. The covering area is divided into a plurality of concentric zones, each of the zones being assigned a pair of particular frequencies or a pair of particular polarization planes. Each zone has one or more substations. Transmission power level of each of the node station transceivers and each of the substation transceivers is adjusted so that fine-weather reception field strength at each end of those radio links having a greater length is greater than fine-weather reception field strength at each end of those radio links having a smaller length, there being a linear relationship between the field strength at each end of each radio link and the length thereof. The minimum azimuth angular spacing between adjacent substations can be reduced by a factor of 1/4 to allow a greater number of substations to be accommodated in the system.

Ikeda Kiyoshi

Papers

Baseband signal switching arrangement for diversity reception in a PCM radio communication system

Multi-direction time division multiplex communication apparatus

Radio communications system with reduced D/U ratio variations

Radio communications system with reduced interference.

Zonal radio communication