The present invention relates to a mobile communication method in which a mobile station performs a handover from a handover source radio base station to a handover target radio base station. The mobile communication method includes the steps of: (A) acquiring, at the handover target radio base station, from the handover source radio base station or a switching center, a key for calculating a first key for generating a certain key used in a communication between the handover target radio base station and the mobile station; and (B) acquiring, at the handover target radio base station, from the switching center, a second key for calculating a first key for generating a certain key used in a communication between a next handover target radio base station and the mobile station.

Mobile communication method and mobile station

Techniques for adjusting transmit power to mitigate both intra-sector interference to a serving base station and inter-sector interference to neighbor base stations are described. The amount of inter-sector interference that a terminal may cause may be roughly estimated based on the total interference observed by each neighbor base station, channel gains for the serving and neighbor base stations, and the current transmit power level. The transmit power may be decreased if high interference is observed by a neighbor base station and increased otherwise. The transmit power may be adjusted by a larger amount and/or more frequently if the terminal is located closer to the neighbor base station observing high interference and/or if the current transmit power level is higher, and vice versa. The intra-sector interference is maintained within an acceptable level by limiting a received SNR for the terminal to be within a range of allowable SNRs.

Power control for a wireless communication system utilizing orthogonal multiplexing

Pilot signal transmission sequences and methods are described for use in a multi-sector cell. Pilots in different sectors are transmitted at different known power levels. In adjacent sectors a pilot is transmitted while no pilot is transmitted in the adjoining sector. This represents transmission of a NULL pilot signal. A cell NULL is also supported in which NULL pilots are transmitted in each sector of a cell at the same time. Multiple pilot signal measurements are made. At least two channel quality indicator values are generated from measurements corresponding to at least two pilot signals of different power levels. The two values are transmitted back to the base station which uses both values to determine the transmit power required to achieve a desired SNR at the wireless terminal. The wireless terminal also reports information indicating its location to a sector boundary.

Pilot signals for use in multi-sector cells

Techniques for efficient signaling to and from a plurality of mobile stations are disclosed. In one embodiment, a subset of mobile stations may be allocated a portion of the shared resource with one or more individual access grants, another subset may be allocated a portion of the shared resource with a single common grant, and yet another subset may be allowed to use a portion of the shared resource without any grant. In another embodiment, an acknowledge and continue command is used to extend all or a subset of the previous grants without the need for additional requests and grants, and their associated overhead. In one embodiment, a traffic to pilot ratio (T/P) is used to allocate a portion of the shared resource, allowing a mobile station flexibility in selecting its transmission format based on T/P.

Scheduled and autonomous transmission and acknowledgement

A flexible OFDM/OFDMA frame structure technology for communication systems is disclosed. The OFDM frame structure technology comprises a configurable-length frame which contains a variable length subframe structure to effectively utilize OFDM bandwidth. Furthermore, the frame structure facilitates spectrum sharing between multiple communication systems.

Flexible OFDM/OFDMA frame structure for communication systems

Systems and methodologies are described that facilitate device-side access point list management. Blacklists of access points unsuitable for providing network access to a related mobile device can be maintained as well as whitelists of suitable access points. The lists can be managed using an interface provided at the mobile device. In addition, lists can be modified according to provisioned network updates. Also, the lists can be of maximum size such that older entries can be purged upon insertion of newer entries based on a number of factors; timed entry deletion is provided as well. Access points in the lists can be stored and presented according to various identifiers related to the access points.

Device managed access point lists in wireless communications

A wireless communication network includes a base station system that transmits sector congestion information to influence mobile station sector selection processing. In an exemplary embodiment, where at least some of the mobile stations being supported by the network autonomously select the network sector from which they wish to receive forward link packet data transmissions, an exemplary base station influences that sector selection processing by transmitting congestion information on a per sector basis. Complementing that transmission by the network, an exemplary mobile station incorporates consideration of the sector congestion information into its autonomous sector selection processing logic. Thus, where potentially large numbers of mobile stations individually select the “best” sector from a candidate set of sectors, the network can perform load balancing by advertising sector congestion levels, so that mobile stations can choose (or avoid choosing) a given sector based at least in part of the congestion information.

Method and apparatus for congestion control in high speed wireless packet data networks

A multicarrier CDMA system allows the number of carrier frequencies supporting a connection to be dynamically varied. The packet stream is divided into one or more substreams depending on the selected number of carrier frequencies and each substream is transmitted on a corresponding carrier frequency. The number of carrier frequencies is selectively varied during transmission of said packet data.

Selective multicarrier cdma network

A method of reverse link power control for a reverse packet data channel in a wireless communication system allows a mobile station to autonomously change its data transmission rate The mobile station transmits packet data over a reverse packet data channel having a data rate variant transmit power level that varies based on a transmit data rate on the packet data channel The mobile station further transmits control signals over a reverse control channel associated with the reverse packet data channel The transmit power level of the reverse control channel is such that the transmit power level does not vary with the transmit data rate on the packet data channel The radio base station measures the strength of the received signals on the reverse control channel, compares the measured strength to a power control set point, and generates a power control signal responsive to the comparison of the control signal to the power control set point

Power Control for Reverse Packet Data Channel in CDMA Systems

Noise is measured at one or more base stations in a mobile communication system during periodic silence periods. A periodic silence period is defined for at least one carrier that is independent of reverse link channel frame boundaries. The radio base stations transmits silence parameters defining the periodic silence period to mobile stations, which stop transmitting during the periodic silence periods. A time reference is provided to the mobile stations to synchronize the silence periods for all mobile stations.

Young C. Yoon

Papers

Device managed access point lists in wireless communications

Method and apparatus for congestion control in high speed wireless packet data networks

Selective multicarrier cdma network

Power Control for Reverse Packet Data Channel in CDMA Systems

Enhancements to periodic silences in wireless communication systems