Abstract: In a method of enabling synchronization for a channel in an OFDM based telecommunication system initially providing a symbol for transmission and selecting at least two carrier frequencies, subsequently determining a respective weighting parameter for the selected frequencies and finally transmitting the symbol on all selected frequencies based on the weighting parameters.

Abstract: In a system applying orthogonal frequency division multiplexing, OFDM, a number of carriers are reserved for communication between unsynchronized nodes (N1, N2). At least one such reserved carrier is assigned to each base station. A sinusoidal signal is transmitted on this reserved carrier during a time period at least equal to two consecutive OFDM symbols. The unsynchronized receiver detects the sinusoidal signal during one of two consecutive OFDM symbol time periods. The existence, the frequency and the signal power of the signal give information about the existence and identity of the transmitter. Also, estimates of relative velocities and distances can be deduced. In preferred embodiments, the sinusoidal signal can also be used to transmit further information by using signal modulation or coding that is independent of the absolute signal phase.

Abstract: A system and a method for wireless linking in a cellular communication system are disclosed such that a mobile station is maintained in simultaneous communication with at least a first node and a second node for access to the cellular communication system. Information going to and from the first node is not identical to the information going to and from the second node. In one embodiment the second node, or secondary access point is a relay node forwarding received information to and from the first node, or primary access point. In another embodiment the second node is another mobile station performing a direct mobile-to-mobile communication (MS-to-MS). In still an embodiment a first wireless link to the first node is for control information only. In still a further embodiment a second wireless link to the second node is only for communication of information from the mobile station or only for communication of information to the mobile station.

Abstract: The object of the present invention is to provide a mechanism for a more efficient carrier search. The object is achieved by a method for sending a signal in a first node. The first node communicates with a second node via radio communication, which radio communication is performed by multi carrier transmission. The first node uses a carrier, being associated with a frequency range. The method comprises the step of transmitting an end-marker signal within or close to the frequency range. The end-marker signal is intended to be received and used by the second node for identifying the frequency range of the used carrier.

Abstract: The invention discloses a method for a cellular communications system, in which traffic is sent in frames, each frame comprising a first number of subframes, with a second number of said subframes being available for at least either uplink or downlink traffic. At least one of said second number of subframes is made to comprise at least three parts, as follows: One part which is utilized for uplink traffic, One part which is utilized for downlink traffic, One part which is utilized as a guard period, with said guard period part being scheduled between the uplink and the downlink parts. The duration of at least two of said three parts may be varied to fit the current system need.

Abstract: The invention relates to a method for moving a maneuverable part of a pan-tilt camera from a first pan-tilt position, having a first pan coordinate and a first tilt coordinate, to a second pan-tilt position, having a second pan coordinate and a second tilt coordinate. The maneuverable part is moved by inverting the maneuverable part of the camera and panning to the second pan coordinate. The first pan coordinate is part of a pan-tilt coordinate system and the second pan coordinate is part of a complementary pan-tilt coordinate system, which represents positions of the inverted maneuverable part. The maneuverable part is moved from the first tilt coordinate to the second tilt coordinate. The first tilt coordinate is part of the pan-tilt coordinate system and the second tilt coordinate is part of the complementary pan-tilt coordinate system. The invention also relates to a corresponding device and a corresponding computer program.

Abstract: A method for use in a cellular, FFT based multi-carrier communications system comprising N sub-carriers, for allocating a set P of sub-carriers to be reserved for potential use as carriers of specific information, comprises the following steps: selecting a number M indicating the number of sub-carriers to be allocated to a set P of sub-carriers, such that L=N/M is an integer allocating the at least two subcarriers of the set P={(n0+m*L) mod N : 0?m<M} for the specific information, n0 being the offset of the lowest numbered subcarrier in P, the elements of P being indices, each referring to the number of a sub-carrier to be allocated. An apparatus for carrying out the method is also disclosed. According to the invention, the sub-channels are maximally spread in frequency, which gives maximum diversity and also enables the use of low-complexity terminals.

Abstract: Radio resources are allocated to communication between a mobile station and a base station. The available set of radio resources may comprise radio resources primarily assigned to a neighboring cell if the 5 mobile station experience an instantaneous low level of co-channel interference from such neighboring cells. The existence of interference is preferably deduced from signal quality measurements of pilot signals. The allocation may concern uplink and/or downlink communication. Devices for performing the measurements are located in the mobile station, while devices for performing the evaluation, selection and actual allocation can be placed in different parts of the communications system—in the mobile station, in a base station or in a core network node, or as a distributed means.

Abstract: A multiple path information transfer system in a cellular radio network includes several receivers (BS-1, . . . , BS-N) for receiving radio signals representing digital information from at least one signal source. From each received radio signal a corresponding digitized baseband signal that contains soft information is extracted. Compressing units (10) compress the soft information to produce compressed baseband signals. These compressed signals are forwarded to a combining unit over a transport network. A de-compressor (16) de-compresses the forwarded signals to at least approximately restore the baseband signals. The de-compressed signals are combined (18-22) and the combined signal is decoded to at least approximately restore the digital information.

Abstract: A relay station (606, 806a, 806b, 906a, 906b, 1006 and 1106) and a method (700) are described herein that enables reliable digital communications to occur between two nodes in a wireless relay based network (600, 800, 900, 1000 and 1100). The wireless relay based network includes a first node (602, 802, 902, 1002 and 1102) that transmits information in coded/modulated digital communications to a second node (604, 804, 904, 1004 and 1104) via one or more relay stations. And, each relay station is capable of (1) receiving (702) a coded/modulated digital communication from the first node; (2) computing (704) a plurality of reliability values for a plurality of information symbols or coded symbols in the received coded/modulated digital communication; and (3) transmitting (706) a coded/modulated digital communication that has the computed reliability values embedded therein to the second node.

Abstract: A set of different pilot structures are designed for use in different environments and/or different user behaviours that are expected to occur in a cell. The radio conditions for a user are estimated. Each user is then assigned an area (108A-E) in resource space for its communication, which has a suitable pilot configuration. In one embodiment, the entire resource space is provided with different pilot structures in different parts (110A-D) In advance and allocation of resources to the users are then performed in order to match estimated radio conditions to the provided pilot structure. In another embodiment, allocation is performed first, and then the actual pilot structure is adapted within the allocated resource space area to suit the environmental conditions.

Abstract: In a system applying orthogonal frequency division multiplexing, OFDM, a number of carriers are reserved for communication between unsynchronised nodes (N1, N2). At least one such reserved carrier is assigned to each base station. A sinusoidal signal is transmitted on this reserved carrier during a time period at least equal to two consecutive OFDM symbols. The unsynchronised receiver detects the sinusoidal signal during one of two consecutive OFDM symbol time periods. The existence, the frequency and the signal power of the signal give information about the existence and identity of the transmitter. Also, estimates of relative velocities and distances can be deduced. In preferred embodiments, the sinusoidal signal can also be used to transmit further information by using signal modulation or coding that is independent of the absolute signal phase.

Abstract: A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signature-length than the signatures in other sets. The different signature-lengths can be optimized for the operational environments involved (e.g., longer signatures for slower-moving mobile stations, and shorter signatures for high-speed mobile stations). Alternatively, at least one differentially-encoded signature is used for random access transmissions, in order to reduce the radio channel's sensitivity to large doppler spreads and frequency errors.

Abstract: Methods and apparatus for synchronization of a transmitter and a receiver are based on orthogonal sequences having optimized correlation properties. The transmitter may generate signed versions of S-Hadamard sequences that are obtained by position-wise scrambling a set of Walsh-Hadamard sequences with a special sequence having complex elements of constant magnitude. The receiver estimates a time location and sequence identity of a received version of the synchronization signal.

Abstract: The present invention relates to a method and an arrangement for communicating packet information in a digital telecommunications system. Through the invention is selected a set of designated communication resources (ch1-chn) from an available amount of resources. Every packet (P) is forward error correction encoded into an encoded packet (Pci), via one of at least two different coding schemes (ci), prior to being transmitted to a receiving party, over the designated communication resources (ch1-chn). An estimated transmission time is calculated for all combinations of coding scheme (ci) and relevant distribution (dj) of the encoded data blocks (B1-B&Ggr;), in the encoded packet (Pci) over the set of designated communication resources (ch1-chn), and the combination (ci,dj) is selected, which minimises the estimated transmission time.

Abstract: A channel optimized vector quantization apparatus includes a device for weighting a sample vector x by a weighting matrix A and a device for weighting a set of code book vectors ĉr by a weighting matrix B. Device form a set of distance measures {dw(Ax,Bĉr)} representing the distance between the weighted sample vector Ax and each weighted code book vector Bĉr. Other device form a set of distortion measures {&agr;i(x)} by multiplying each distance measure by a channel transition probability Pr|i that an index r has been received at a decoder when an index i has been sent from an encoder and adding together these multiplied distance measures for each possible index r. Finally device determine an index imin corresponding to the smallest distortion measure &agr;i(x) and represents the sample vector by this index imin.

Abstract: In a digital cellular radio communication system, a base station selects a speech/channel encoding mode based on measurements of the local radio environment. The mobile station determines the selected mode by trial decoding possible modes to find the most probable mode and uses the same mode for transmission to the base station on the return link. The coding gain/loss obtained by this mode switching may be used to adjust the output power of transmitters, thereby reducing the overall interference level in the system.

Abstract: A power control system in a TDMA radio communication system has traffic channels which are associated with a set of speech/channel encoding modes. Each mode has a different mix of speech encoder bit rate and data protection bit rate but the same total available gross bit rate. The transmitter includes a power control unit that replaces a mode allocated to a channel by another mode having either a higher or a lower data protection bit rate and either a lower or a higher speech encoder bit rate if the sound to be encoded requires either a lower or a higher speech encoding bit rate. The power control unit also controls a power adjustment unit that either reduces or increases the output power of the transmitter to a lower or a higher level such that an estimated decoded speech quality measure at the receiver is substantially constant.

Abstract: A method and system for transmitting signals using unequal error protection (UEP). According to the method, symbols having a higher level of coding protection are detected and decoded first, soft reliability information is generated, and then the previously detected symbols and soft reliability information are used to detect and decode symbols having the next lower level of coding protection. The symbols having lower levels of coding protection benefit from the decoding of all previous classes of symbols. Data symbols can be interleaved to further enhance system performance.