Ntt Docomo, Inc.

Moo Ryong Jeong

Fujio Watanabe

Toshiro Kawahara

Ismail Guvenc

Xia Gao

Gang Wu

Hiroyuki Ishii

Nobuhiko Miki

Huseyin Arslan

Hidetoshi Kayama

Hiroshi Inamura

Anxin Li

Xiangming Li

Mustafa Emin Sahin

Fujio Wantanabe

A system for securing radio access with inter-eNB carrier aggregation including a primary eNB configured to secure transmission with a user equipment. The primary eNB generates a base key and derives a set of derived keys used to secure transmission on a set of radio bearers that correspond to the set of derived keys. The system for securing radio access with inter-eNB carrier aggregation also including a secondary eNB configured to secure transmission with the UE using at least one of the set of derived keys received which corresponds to a radio bearer from the set of radio bearers used by the SeNB.

Secure radio access with inter-eNB carrier aggregation

A user terminal reports a group radio quality of each of radio resource groups to a base station at a first frequence. The base station reports an allocated radio resource group to be allocated for radio communication with the user terminal to the user terminal. The user terminal reports unit radio qualities of radio resource units contained in the allocated radio resource group to the base station at a second frequence that is higher than the first frequence. The base station performs radio resource scheduling on the basis of the unit radio qualities.

Radio communication system, base station, user terminal, and communication control method

In one embodiment, the unit share data rates for a plurality of mobile stations are determined with regard to two resource groups. A differentiation factor for each mobile station is formed from a ratio of its unit share data rates. The resulting differentiation factors are sorted and classified into two groups according to a proportional fair border determining function. A first one of the resource groups is allocated to the mobile stations corresponding to a first one of the differentiation factor groups. Similarly, a second one of the resource groups is allocated to the mobile stations corresponding to a remaining second one of the differentiation factor groups.

Proportional-fair radio resource management

Packet communication method and system in which a packet destined for a terminal is provided service according to a service table indexed by packet classification and the terminal's power mode. The service table may specify for a connection a predetermined quality of service or discarding the packet. For a power mode having an alerting (i.e., paging) mechanism, the service may include alerting the terminal. The service table may also include a network edge point's own service requests and service requests from terminals, provisioning servers, and handoff sources. For a multicast or broadcast packet, as each terminal may be in a different power mode, the associated service in the service table may therefore be different for each terminal. In that case, the packet is provided with service so that any given terminal is provided with at least the quality of service specified in the service table. Thus, a multicast or broadcast packet is discarded when the service specified for all terminals is 'discard.' Each terminal is alerted, however, if the associated service includes alerting the terminal. During handoff, a part of service table associated with the terminal can be transferred from the handoff source to the handoff destination.

Power mode aware packet communication method and apparatus

Systems and methods are provided for a distributed inter-cell interference avoidance (ICIA) technique for avoiding co-channel interference between femtocell networks and macrocell networks. At the macrocell, user equipments sense the downlink (DL) spectrum and detects whether there are any nearby interfering femtocells. If there is any interference, a macrocell base station appropriately re-schedules the DL resources and also uses a mapping function to re-schedule uplink (UL) resources based on the re-scheduled DL resources. At the femtocell, a femtocell base station senses the UL spectrum to detect for interference from nearby macrocell users. If there is interference, femtocell gives priority for use of the resources to the macrocell by releasing UL resources. Femtocell may also use the same mapping function to obtain the DL resources used by the macrocell and to re-schedule DL and UL resources of the femtocell to avoid using the DL and UL resources of the macrocell.

System and method for inter-cell interference avoidance in co-channel networks

A method and apparatus is disclosed herein for transmitting data in a network (e.g., a relay network). In one embodiment, the method comprises performing pre-transmission of a packet to hops to enable the base station and the plurality of hops to transmit the packet synchronously to one or more mobile stations in the wireless communication system; and performing one or more re-transmissions of the packet at a first set of one or more hops in the system during a delay due to pre-transmissions at a second set of one or more hops in the system.

Method for ARQ-enabled pre-transmissions in multicast and broadcast services of relay networks utilizing the idle periods

In a fast active scanning wireless network apparatus and method for quick determination of available access points, information about a candidate set of available access points is obtained, and a candidate access point is identified from the candidate set. A mobile station then queries the candidate access point with a probe request that designates the candidate access point as a sole responder. The probe request prevents other access points from contending for the medium of communication between the mobile station and the designated sole responder access point by excluding the attempt by other access points to transmit probe responses. The apparatus and method thus increases the probability of a fast and successful probe request from the mobile station and subsequent response from the designated access point. The designated access point may also respond with a probe response of high priority, preventing intervention of communication.

Fast active scanning wireless network apparatus and method

A femtocell increases efficiency and coverage of a macrocellular network operating in a co-channel manner within the macrocell spectrum by selecting subcarriers for its mobile station using both the subcarrier allocation map received from the macrocell and a spectrum sensing operation. Interference is avoided by selecting only subcarriers not allocated by the macrocell and subcarriers allocated to users not nearby to the femtocell. Interference is eliminated from the received signals using co-channel interference avoidance techniques. Selection of subcarriers for femtocell use may take into consideration inter-carrier interference detected.

OFDMA-based co-channel femtocell

A method and a communication system including femtocells within a macrocell efficiently manage interference between the different femtocells, and between each femtocell and a macrocell. An efficient frequency assignment scheme for the femtocells minimizes interference between a femtocell and a macrocell and among different femtocells using a spectrum-sensing technique carried out by the femtocells. The frequency assignment scheme selects a suitable channel from a set of candidate channels and ensures that the femtocell has an acceptable coverage area even when it is close to the macrocell base station (BS). The frequency assignment scheme favors a co-channel implementation to take advantage of the hand-off and cell search characteristics of the co-channel implementation. In one embodiment, a joint power control and frequency band assignment technique is used, which partitions the coverage area of the macrocell into an inner region, a power control region, and an outer region. Depending on a femtocell's location, it is assigned a certain power level and a frequency band. Power control may be used within the power-control region while, in the other regions, a fixed transmission power may be used.

Femtocell channel assignment and power control for improved femtocell coverage and efficient cell search

A method and apparatus is disclosed herein for synchronized multi-link transmission in an ARQ-enabled multi-hop wireless network. In one embodiment, the method comprises performing pre-transmission of a packet to hops to enable a base station and the plurality of hops in the network to transmit the packet synchronously to one or more mobile stations in the wireless communication system; and performing one or more re-transmissions of the packet at a set of one or more hops forming a path in the network if time remaining before a synchronized transmission time for the path as a whole is greater than a threshold.

Synchronized multi-link transmission in an ARQ-enabled multi-hop wireless network

In a fast active scanning wireless network apparatus and method for quick determination of available access points (), information about a candidate set of available access points () is obtained, and a candidate access point is identified from the candidate set. A mobile station () then queries the candidate access point with a probe request that designates the candidate access point as a sole responder. The probe request prevents other access points from contending for the medium of communication between the mobile station and the designated sole responder access point by excluding the attempt by other access points () to transmit probe responses. The apparatus and method thus increases the probability of a fast and successful probe request from the mobile station and subsequent response from the designated access point (). The designated access point may also respond with a probe response of high priority, preventing intervention of communication.

Active scanning method in a wireless network for fast determining available access points () using inter-AP (Access Point) communication is described. In the scanning method, a mobile station () sends Probe Request for Proxy frame to the current AP () serving the mobile station (). In response to the Probe Request for Proxy frame, the current AP () send Proxy Probe Request packet to the appropriate APs (). In response to the Proxy Probe Request packet, the neighbor APs () send Probe Response frame to the mobile station () on its operating channel. Since the mobile station () moves to the channel being examined after sending the Probe Request for Proxy frame, it receives the Probe Response frame if it is in the coverage area of the neighbor AP (). The content of Probe Response frame provides the mobile station () with the information to be used in handoff decision and network join procedures. Thus, the mobile station () neither has to move to the channel to be examined nor send Probe Request frame on that channel. This enables active scan to be initiated even when the neighbor AP () is operating in PCF (Point Coordination Function) and the network is in CFP (Contention Free Period), during which unassociated mobile stations (including the scanning mobile station) cannot send packets.

Proxy active scan for wireless networks

A method is provided for MIMO uplink communications between a base station and a wireless station with more than two antennae. The method includes: (a) negotiating between the base station and the wireless station uplink MIMO/cooperative MIMO capabilities, using a message exchange protocol in which a message exchanged comprises a field for specifying uplink MIMO/cooperative MIMO capabilities; (b) the base station receiving a request from the wireless station for data transmission; (c) the base station sending the wireless station an allocated resource and an uplink MIMO/cooperative MIMO method for uplink transmission; (e) the wireless station mapping data symbols to the allocated resource with proper pilot pattern; and (f) the base station detecting the data symbols from the channel.

Uplink multiple-input-multiple-output (MIMO) and cooperative MIMO transmissions

Methods for increasing power saving in a station that sends or receives frames in an ad hoc wireless network (e.g., IBSS), while allowing the station to enter a power-saving mode quickly upon completion of scheduled tasks. At the same time, a method of the present invention allows two stations in the ad hoc wireless network to infer each other's power management mode without requiring an ATIM/ACK exchange between the STAs within an ATIM window. Consequently, a station may enter a power-saving mode promptly without impairing the station's ability to receive packets. In one embodiment, a 'more data' field is used between stations to exchange information. Stations with various computation abilities provide information under different time constraints. The stations may enter power-saving modes that send multicast/broadcast frames or use promiscuous mode within an ATIM window.

Method and apparatus for power saving in beacon generation of wireless networks in ad hoc mode

Channel scanning for wireless networks, such as Wireless Local Area Networks (WLANs), generally provides a wireless station with the information on the available WLAN resources, such as the frequency band and the maximum transmission power. The present invention provides safe and fast domain-aware channel scanning, enabling a wireless station to comply with applicable local regulations, in spite of the possibility of domain changes, with short channel-scanning time. Fast channel scanning is accomplished by active channel scanning if valid domain information is available and there is no possibility of domain change. Also, domain-independent channels, if any, are first scanned using active scan to get domain information faster.

Growing community of inventors

Albany, CA, United States of America

Moo Ryong Jeong