摘要:
An OCDMA transmission arrangement involves encoding both first and second nominally orthogonal polarization signals with a same long code, and transmitting the long-encoded first and second nominally orthogonal polarization signals from respective first and second transmission sources to at least one destination. A corresponding OCDMA demodulating arrangement demodulates the first and second nominally orthogonal polarization signals that were transmitted from respective first and second transmission sources after having been encoded with the same long code. The demodulation arrangement involves receiving the encoded first and second nominally orthogonal polarization signals, and applying the same long code to the received encoded first and second nominally orthogonal polarization signals.
摘要:
A broadband terrestrial message delivery system includes a plurality of wireless communication devices (WCDs), each including a receiver and transmitter, the WCDs capable of not only receiving messages destined for a subscriber associated with a particular WCD, but further capable of acting as a relay point to move messages to and from other subscribers. Message diffusion includes relaying the messages in accordance with all earmark that specifies both the total number of times (N) a message is to be repeated, and the number of times (i) the received message has already been repeated. Methods of improving the spectral efficiency of such a message diffusion architecture include adding a propagation ring width control parameter (J) to the earmark such that a WCD acting in relay mode transmits no more than J repetitions of the message; and providing sectorization such that several sectorized message pathways in a cell may be simultaneously active.
摘要:
Methods and apparatus are disclosed to provide orthogonal multiple access communication in a return link of a satellite communication system. In one embodiment, a closed loop control of a transmit parameter associated with transmission of signals may be performed. In addition, changes in motion of a terminal are monitored such that an open loop control of the transmit parameter is performed, if the detected change meets a certain threshold. For example, an open control is performed if an abrupt or sudden motion is detected.
摘要:
Systems, methods and apparatus for configuring and accessing a random access channel in a CDMA communication system are disclosed. The number of users supported by a random access channel can be optimized by assigning a distinct time of arrival to each of a plurality of users. Each of the users can be time synchronized and can transmit data at a time that compensates for a propagation delay to allow the data to arrive at the destination receiver at the assigned time. In a CDMA system, each of the users can transmit data that is spread with the same spreading code, provided the cross correlation properties of the code are sufficient to allow identification of a source that is time offset relative to another user. The time of arrival can be determined based on the number of active users, and can be assigned as often as each transmission by each user.
摘要:
A satellite is linked to a number of gateways by a number of feeder links. When a degraded link is detected among the feeder links, communications are switched from the degraded link to a diversity link shared among the feeder links. In one embodiment, said diversity link is connected to a diversity gateway located outside a service area of the satellite. In another embodiment, the diversity link comprises channels distributed among the feeder links within the service area.
摘要:
Systems and methods for burden sharing in satellite based communication systems are disclosed. One or more users in a satellite based communication system may experience signal degradation or signal fading that can occur for an extended period of time, such as when the fade is due to rain fade. The system can improve a communication link with a particular user by varying the data rate. The data rate can be varied by reducing a coding rate to compensate for low signal quality. In a time multiplexed communication system where multiple users time multiplex the available communication bandwidth, the system can concurrently adjust a time allocated to a user based in part on the coding rate. The time allocated to a user can be increased for decreased coding rates in order to maintain a substantially stable symbol rate to the user for each time multiplex cycle of users.
摘要:
A mechanism that enables a gateway to dynamically determine which of two transmission signal polarizations is best received by a wireless communication device having a nominally linear antenna. A first pilot and second pilot signals, having different polarizations and orthogonally encoded, are transmitted to the communication device. The communication device determines the relative or absolute signal strengths of the first and second pilot signals and transmits this information to the gateway. The gateway then selects the polarization having the strongest associated signal strength to transmit content-bearing signals to the communication device. Alternatively, the communication device may also determine the phase difference between the first and second pilot signals and transmit this information to the gateway. The gateway can then transmit content-bearing signals using a proportional amount of signal power on each the first and second polarizations and use the proper phasing to approximate the polarization orientation of the communication device.
摘要:
Communication diversity using a plurality of satellites is disclosed. The satellites can support multiple regions corresponding to multiple satellite beams. Each satellite can support all regions in the reverse direction and each satellite can be designated as a primary satellite for one of the multiple regions corresponding to one of the multiple satellite beams. Each satellite can receive from any of the regions reverse link signals broadcast by, for example, a mobile station. Each satellite can communicate the received reverse link signals to, for example, a base station or gateway where the signals can be combined to increase signal quality. A mobile station receives forward link signals from the primary satellite and monitors a signal quality from the primary satellite and from a secondary satellite. If the signal quality from the primary satellite drops below a threshold value, the communication signal is transferred to the secondary satellite.
摘要:
Various schemes are provided that facilitate a communication handoff from a current base station to a target base station. One feature provides for reducing the search space that a base station searches by providing it with the position/location and/or velocity of an access terminal with which it attempts to communicate. Having the position and/or velocity of the access terminal, a current or target base station is able to reduce its search space (e.g., direction, frequency range, and/or time window) for the access terminal. Another feature provides for selectively and gradually increasing the power of a pilot signal originating from the access terminal during the handoff acquisition period to a target base station. By increasing the pilot signal power, the base station has a better chance of acquiring the signal and do so more quickly.
摘要:
An apparatus and method for a wireless communication system in which a forward/uplink portion and a return/uplink portion are assigned within an available frequency bandwidth is disclosed. More particularly, a service area is divided into multiple regions. The assignment of the forward/uplink portion of the return/uplink portion is shuffled in the multiple regions. The apparatus and method may be implemented in a multi-beam wireless communication system.