Abstract:
A method and apparatus for controlling transmission power in a mobile communication system is disclosed. The method disclosed provides for a closed-loop power control method for variable rate transmissions. The power of transmissions is varied in accordance with the rate of the frames of data being transmitted. The transmission power between the rates can be a fixed or variable difference.
Abstract:
A portable wireless communications device such as a telephone handset (10, 110) having a vertically corrected antenna module (34, 134) pivotally secured to the handset (10, 110) for rotation about a first pivot axis (40, 140). The antenna module (34, 134) can be rotated into a predetermined orientation, independent of handset orientation. An antenna (24, 124) mounted on the module (34, 134) is oriented vertically when the module (34, 134) is in the predetermined orientation. When the antenna module (34, 134) is rotated for use, a mechanism incorporated in the module (34, 134) support structure automatically rotates the antenna module (34, 134) about a second pivot axis (190) which is substantially perpendicular to the first (40, 140). This second rotation places the antenna (24, 124) at an angle that compensates for tilting of the handset (10, 110) during use about an axis parallel to the second axis (190), or along the first (40, 140). That is, the antenna (24, 124) is shifted by a preselected angle in vertical orientation, typically around 10-15 degrees, in a direction perpendicular to the first direction of rotation to compensate for positioning a speaker and microphone (26, 28) for use.
Abstract:
Method and apparatus for enhancing diversity in spread spectrum type communication systems by creating pseudo-multipath conditions or links for certain communication signals. The invention provides alternative or additional signal paths (82, 84, 86 and 92, 96, 98, 99), for signals being transferred between gateways (20, 22) and communication system users (16, 18) through one or more satellite repeaters (12, 14). These additional paths are used to establish and maintain adequate signal diversity as well as certain signal links by remote subscribers (16, 18) in heavy urban areas. In further aspects of the invention, diversity enhancers can employ high gain parabolic antennas (76) and tracking mechanisms (100), or passive reflective surfaces (130). Signals can be relayed to subscriber units in canyon type blocked areas (18B, 18C, 18E) or within structures (18D).
Abstract:
A dual-band octafilar helix antenna (100) operational at two frequencies, while maintaining a relatively small package size. The dual-band octafilar antenna (100) is manufactured by disposing radiators (104, 1304, 2304, 2306) and a feed network (308, 1308, 2308, 2310) onto a flexible substrate (108, 2400) and forming the substrate into a cylindrical shape to obtain the helical configuration. The dual-band octafilar helix antenna (100) includes four active radiators (104, 2304) which are matched to a first frequency and disposed on a radiator portion (204) of the flexible substrate (108). Four additional radiators (1304, 2306), which may be either passive or active radiators, are matched to a second frequency, are also disposed on the radiator portion (204) of the substrate (108, 2400) and interleaved with the active radiators (104, 2304). At least one feed network (308, 1308, 2308, 2310) is provided on a feed portion (208) of the substrate (108, 2400) that provides 0 DEG , 90 DEG , 180 DEG , and 270 DEG signals to active radiators (104, 2304). The sets of radiators (104, 1304, 2304, 2306) and associated feed networks (308, 1308, 2308, 2310) may be formed on opposing sides of a single substrate (108, 2400) or on spaced-apart layers (2500, 2502) in a multi-layered support substrate design.
Abstract:
A method and system incorporating the use of interference cancallation during the forward link portion of a wireless telecommunication system is described. A wireless telephone system subscriber unit (104) receives multiple forward link signals (102) and estimates the data being transmitted via each forward link signal (102). In response to this estimate an ideal waveform is calculated (309). For each forward link signal (102), the ideal waveforms associated with the other forward link signals are subtracted from the actual energy level of that forward link signal before data being transmitted is determined. In the preferred embodiment, the forward link signals are processed in accordance with code division multiple access spread spectrum techniques, and the estimation of the data being transmitted is performed via the use of a fast Hadamard transform (308). In an alternative embodiment, the estimation of data is performed on a single channel, or sub-set of the channels, carried by the forward link signals, with at least the associated signal level of a pilot channel being estimated.
Abstract:
A 180 DEG power divider (1100) accepts an input signal and splits it into two ouput signals that are equal in amplitude and differ in phase by 180 DEG . In a first region (1132), an unbalanced input signal travels along a trace (1108) on a circuit surface of a substrate (108). On the opposite surface is a ground plane (1104). In a second region (1134), the ground plane tapers (1146) to a width that is substantially equal to the width of the signal trace (1108). As a result, opposite the signal trace (1108) is a return signal trace (1109) of substantially the same width. In this region (1134), the signal is a balanced signal, and for the current flowing in the signal trace (1108), there is an equal but opposite current flowing in the return signal trace (1109) on the opposite side. In a third region (1136), the return signal trace (1109) is brought to the circuit surface of the substrate (108) and a second ground plane (1112) is provided on the opposite surface. This second ground plane (1112) plane is floating with respect to the first ground plane (1104). The return signal differs in phase from the other signal by 180 DEG .
Abstract:
The wireless local loop system employs cellular technology to provide telephone service to fixed telephones of remote stations (20) having otherwise conventional handsets. The remote station (20) emulates a conventional public switched telephone network by providing an artificial dial tone from the handset of the remote station, after the handset is taken off-hook. The artificial dial tone is locally generated (112) by the remote station. The system, however, delays providing the dial tone if the system is busy, i.e. if the system is under a load condition. To this end, the system monitors load levels (20) and transmits signals to the remote stations indicating load conditions. A remote station (20), prior to granting at dial tone to the user, receives the load condition signals, determines whether the system is currently under load (211) and, if so, defers the dial tone (213). Hence, if the system is under a load condition, such that no lines or frequency channels are available, the user is not presented a dial tone until a line or channel becomes available. By deferring the dial tone until a line or channel is available, the wireless local loop system more effectively emulates a PSTN.
Abstract:
The process and apparatus of the present invention limits the output power of a radio in response to the temperature of key components of the radio. Temperature sensors (1025) measure the temperature of the components and send the temperature signals to power control circuitry (1030). The transmit power is measured (1020) at the output of the power amplifier (1015). As the temperature increases, the power control circuitry (1030) reduces the transmit power to reduce the temperature of the key components. The power is monitored so that it is not reduced below the power level required by standards.
Abstract:
Method and apparatus for receiving signals in gateways for satellite repeater type spread spectrum communication systems making more efficient use of data transfer capacity and diversity processing. Several communication signals are received by multiple analog receivers (62M) and converted into digital format. The digital communication signals are transferred from each analog receiver (62M) into a series of demodulation or FHT modules (164) in which they are first despread into encoded data symbols using predetermined PN coding sequences, and then mapped into symbol energy metrics using orthogonal transformers (192), such as fast Hadamard transformers. The transformation output for each communication channel from each analog receiver (62M) is input to a single metric receiver (166N) for a data channel or subscriber, where it is subjected to conventional metric signal processing to reconstruct the data. A set of dedicated modules (164MN) is coupled to each analog receiver (62M) for handling each diversity path or subscriber active communication system channel being transferred through that receiver or analog path. Each demodulation or FHT module (164MN) comprises despreading elements (176, 178) and FHT components (192) that are easily distributed in processing arrays within the gateway.
Abstract:
The present invention discloses a variable rate transmission system wherein a packet of variable rate data is modulated in accordance with a traffic channel sequence supplied by a traffic PN generator (63) if the capacity of said traffic channel is greater than or equal to said data rate of the packet. If the capacity of said traffic channel is less than said data rate, the packet of variable rate data is modulated in accordance with the traffic channel sequence supplied by the traffic PN generator (63) and in accordance with at least one overflow channel sequence supplied by an overflow channel generator (65). The present invention further discloses a receiving system for receiving variable rate data where a received packet of variable rate data is demodulated in accordance with a traffic channel sequence supplied by a traffic PN generator (104) if the capacity of said traffic channel is greater than or equal to a data rate of said packet. If the capacity of said traffic channel is less than said data rate of the packet of variable rate data, the received packet is demodulated in accordance with a traffic channel sequence supplied by a traffic PN generator (104) and in accordance with at least one overflow channel sequence supplied by an overflow channel generator (120).