Showing papers by "Stefan Parkvall published in 2008"

LTE-Advanced - Evolving LTE towards IMT-Advanced

Abstract: This paper provides a high-level overview of some technology components currently considered for the evolution of LTE including complete fulfillment of the IMT-advanced requirements. These technology components include extended spectrum flexibility, multi-antenna solutions, coordinated multipoint transmission/reception, and the use of advanced repeaters/relaying. A simple performance assessment is also included, indicating potential for significantly increased performance.

3G Evolution, Second Edition: HSPA and LTE for Mobile Broadband

Abstract: Reflecting the recent completion of LTEs specification, the new edition of this bestseller has been fully updated to provide a complete picture of the LTE system. The latest LTE standards are included on the radio interface architecture, the physical layer, access procedures, MBMS, together with three brand new chapters on LTE Transmission Procedures, Flexible Bandwidth in LTE and LTE evolution into IMT-Advanced. Key technologies presented include multi-carrier transmission, advanced single-carrier transmission, advanced receivers, OFDM, MIMO and adaptive antenna solutions, advanced radio resource management and protocols, and different radio network architectures. Their role and use in the context of mobile broadband access in general is explained. Both a high-level overview and more detailed step-by-step explanations of HSPA and LTE implementation are given. An overview of other related systems such as TD SCDMA, CDMA2000, and WiMAX is also provided.The new edition has up-to-date coverage of the recently published LTE Release 8 radio-access standard, giving the reader insight into the ongoing and future process of LTE and LTE-Advanced standardisation. Coverage on LTE in this edition includes (an extra 160 pages): Easy-to-access overview of the LTE protocol layers Complete description of LTE physical layer including reference signals, control signalling, multi-antenna transmission schemes Covers both FDD and TDD, their fundamental difference and their impact on the LTE design Detailed description of access procedures including cell search, random access, broadcast of system information Transmission procedures, including retransmission protocols, scheduling, uplink power control Evolution towards IMT-Advanced ("4G") This book is a must-have resource for engineers and other professionals in the telecommunications industry, working with cellular or wireless broadband technologies, giving an understanding of how to utilize the new technology in order to stay ahead of the competition.The authors of the book all work at Ericsson Research and are deeply involved in 3G development and standardisation since the early days of 3G research. They are leading experts in the field and are today still actively contributing to the standardisation of both HSPA and LTE within 3GPP.* Includes details of the standards and technologies (160 new pages): LTE radio interface architecture, LTE physical layer and LTE access procedures* Contains three brand new chapters on LTE: Transmission Procedures, Flexible Bandwidth and LTE Evolution and expanded details on the physical layer (total LTE content is 270 pages)* Examines the latest developments in the evolution of LTE into IMT-Advanced, the next stage of 3G Evolution* Gives clear explanations of the role of OFDM and MIMO technologies in HSPA and LTE* Outlines the System Architecture Evolution (SAE) supporting LTE and HSPA evolution

Uplink scrambling during random access

Abstract: The technology described in this case facilitates random access by a user terminal with a radio base station. A user terminal determines one of a first type of uplink scrambling sequences and generates a random access message using the determined one of the first type of uplink scrambling sequences. The random access message is transmitted to the base station. The user terminal receives from the base station a second, different type of uplink scrambling sequence and uses it for subsequent communication with the radio base station. For example, the first uplink scrambling sequences may be specifically associated with the radio base station's cell area or a random access radio channel associated with the radio base station, but they are not specifically assigned to any user terminal, and the second uplink scrambling sequence may be selected from a second set of uplink scrambling sequences specifically assignable to individual user terminals.

Information on reference signal structure for neighbouring cell measurements

Abstract: The present invention relates to cellular radio communication and in particular to providing information on neighbour cells to enable terminals to perform neighbour cell measurements. In the prior art the terminal attempts to make neighbour cell measurements in a reference signal structure that is the same in the neighbour cell as in the cell the terminal camps in. The present invention is based on the insight that the reference signal structure may differ between neighbouring cell for example in the situation of an MBSFN area that is restricted to a region of all cells of a radio network, or in the situation of TDD mode being applied there may be different regions with different allocation of sub-frames for transmission in the uplink and downlink directions. The present invention solves the problem by broadcast information in a cell indicative of the reference signal structure in neighbour cells.

Anchor carrier selection in multi-carrier wireless network

Abstract: Mechanism to receive control signals transmitted from a base station (210, 510, 910) to the user equipment (220, 520, 920) in a manner that minimizes power consumption on the user equipment (220, 520, 920) while still maintaining some acceptable level of performance is described. The user equipment (220, 520, 920) periodically measures the signal quality of component carriers used by the base station (210, 510, 910) and requests control signaling (anchor) carrier reselection. Either a single component carrier can be chosen if the single carrier has sufficient quality or multiple component carriers can be selected when the quality of the single quality is low. The anchor carrier reselection may also be triggered to manage the system as a whole. For fast moving user equipments (220, 520, 920), anchor carrier hopping pattern can be provided to increase robustness and reduce reselection signaling overhead.

Control channel formulation in OFDM systems

Abstract: Control channel information is formulated for transmission in orthogonal frequency division multiplexing (OFDM) systems. In an example embodiment, a method entails formulating control channel information for a transmitting device operating in an OFDM system in which a control channel spans n OFDM symbols, with n being an integer. The method includes acts of allocating, creating, and mapping. Control channel data is allocated to at least one set of resource element groups. At least one order for the set of resource element groups is created in accordance with one or more permutation mechanisms that involve at least one interleaving sequence having a low cross-correlation property. The set of resource element groups is mapped to resource elements of the n OFDM symbols of the control channel responsive to the order that is created using the permutation mechanism(s). The permutation mechanisms may include interleaving sequence(s) and/or cyclic shift(s).

Measurement of cell-specific reference symbols in the presence of mbms single frequency network transmissions

Abstract: A network unit of an own cell is operated in a radio communication system utilizing a radio interface that includes a radio frame made up of a number of sub-frames. The own cell serves one or more user equipments. Operation includes obtaining information about a scheduling of MBSFN data transmissions in one or more neighboring cells. The information thereby obtained is used to generate an information signal that, for a given sub-frame, enables the one or more user equipments to determine whether neighboring cell measurements can be performed using a unicast group of Orthogonal Frequency Division Multiple access (OFDM) symbols. The information signal is transmitted to the one or more user equipments, which can then use the information to determine how to locate cell-specific reference symbols when doing measurements of neighboring cells.

Method and devices for providing enhanced signaling

Abstract: Methods and devices for introducing enhanced signals into a wireless environment. The enhanced signals provide for functionality that is not specified in a communication standard corresponding to a standard of a legacy terminal. The enhanced signals can be utilized by a non-legacy terminal. The legacy terminal is incapable of processing the enhanced signals and is unable to detect the presence of the enhanced signals.

Key features of the LTE radio interface

Abstract: Mobile broadband based on high-speed packet access (HSPA) technology is already a great success. But even so, to meet future demands for mobile broadband services, the industry must further improve service delivery, for example, through higher data rates, shorter delays, and even greater capacity. These are the very targets of 3GPP radioaccess networks, specifically through HSPA Evolution and LTE. Ericsson is committed to the development of HSPA and LTE as can be seen through an active driving role in standardization and open prototyping. Examples of improved performance compared with early 3G systems include peak data rates in excess of 300Mbps, delay and latencies of less than 10ms, and manifold gains in spectrum efficiency. LTE can be deployed both in new and existing frequency bands and it facilitates simple operation and maintenance. In addition, LTE both targets smooth evolution from legacy 3GPP and 3GPP2 systems and constitutes a major step toward IMT-Advanced (International Mobile Telecommunication – Advanced, sometimes referred to as 4G). In fact, LTE includes many of the features originally considered for a future 4G system.

Drx functionality in multi-carrier wireless networks

Abstract: Mechanisms to provide independent DRX (discontinuous reception) functionalities for individual carriers of a multi-carrier wireless network (200) are described. DRX is a higher layer functionality indicating which TTIs (transmission time intervals) a user equipment (220) needs to read for control signals. Operating in the DRX cycle allows the user equipment (220) to reduce battery consumption. A connection is established between a base station (210) and the user equipment (220) over a plurality of carriers, where for each carrier, an independent DRX cycle is established. The plurality of carriers include anchor carriers which can carry commands from the base station (210). The anchor carriers have shorter DRX cycles than the non-anchor carriers. When a large amount of download data is to be transferred, the DRX cycles of multiple carriers are overridden and used for transfer to achieve fast download rates. The override commands are sent from the base station (210) to the user equipment (220) prior to the transfer.

Signalling Resource Allocation in a Telecommunications Network

Abstract: The present invention provides a method, a radio base station (40) and a mobile terminal (50) for allocating resources in a telecommunications network, where communications between the radio base station (40) and the mobile terminal (50) take place over a plurality of carriers. The method comprises transmitting and receiving a resource allocation message comprising one or more bits. Each of the bits corresponds to a number of resource blocks, where the number is determined from the ratio of the aggregate bandwidth of the plurality of carriers divided by the bandwidth of the carrier over which the resource allocation message is sent.

Uplink Power Control for Power Limited Terminals

Abstract: Transmit power control methods and apparatus are disclosed. In several embodiments, a mobile terminal is configured to effectively ignore “UP” transmit power control commands in the event that the mobile terminal is operating in a power-limited state. In an exemplary method for controlling transmit power at a mobile terminal, a plurality of transmit power control commands are received. An accumulated power control value is adjusted in response to each transmit power control command that directs a negative adjustment in transmit power. However, the accumulated power control value is adjusted in response to a transmit power control command that directs a positive adjustment in transmit power only if the mobile terminal is not in a power-limited state. Transmit power settings for each transmission are calculated based on the accumulated power control value and the one or more radio link parameters.

Subframes in a cellular communications system

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.

Channel Sounding Using Multiple Sounding Configurations

Abstract: More than one set of sounding signal configuration parameters are determined for the same mobile terminal. The mobile terminal uses the sets of configuration parameters to generate different sounding reference signals which can be used for different purposes such as estimating timing and channel quality. In one embodiment, a method of configuring uplink sounding transmissions by mobile terminals in a wireless communication network is characterized by determining different sets of configuration parameters for sounding signal transmissions for a given mobile terminal (200). The different sets of configuration parameters are transmitted to the mobile terminal, allowing the mobile terminal to generate different sounding signals for different uses by the wireless communication network (202).

Multicarrier communication system employing explicit frequency hopping

Abstract: Variable bandwidth assignment and frequency hopping are employed to make efficient use of radio resources. Variable bandwidth assignment is achieved by dynamically allocating different numbers of subcarriers to different mobile terminals depending on their instantaneous channel conditions. The frequency hopping patterns are determined “on-the-fly” based on the current bandwidth assignments. The bandwidth assignments and frequency hopping patterns are signaled to the mobile terminals in a scheduling grant.

Detection and efficient use of broadcast-only modes of cellular communication system operation

Abstract: Operation of a network node (800) in a mobile communication system that serves a User Equipment (UE) includes ascertaining (801 ) whether the network node (800) is operating in a broadcast-only mode. If so, then broadcast channel information is transmitted (803) on a physical multicast/broadcast channel (MCH). Otherwise, the broadcast channel information is transmitted (805) on a physical broadcast channel (BCH). To inform the UE of where to find the broadcast channel information, the network node (800) transmits (807) an indicator to the UE, wherein the indicator indicates whether the broadcast channel information is conveyed via the physical broadcast channel (BCH) or the physical multicast/broadcast channel (MCH). The indicator can be included within signals that are also used to enable a UE's cell search procedure.

Method and apparatus in a telecommunication system

Abstract: Method and apparatus in a communication unit (400) employing a wireless TDD or half duplex FDD transmission arrangement when communicating with a data sending party, for scheduling feedback reports for data blocks in received RX sub-frames, in TX sub-frames available for transmission. An obtaining unit (402) in the communication unit receives allocation parameters (P) for the connection where the number of required feedback reports is greater than the number of allowed feedback reports. A scheduling unit (404) in the communication unit then schedules feedback reports (FR) in available TX sub-frames according to a predetermined spreading rule also known by the data sending party, dictating that the feedback reports are spread out or distributed evenly over the available TX sub-frames. In this way, the number of feedback reports in a TX sub-frame can be reduced.

Scheduling in a cellular system

Abstract: In a cellular system ( 100 ), transmissions are made ( 410 ) in subframes ( 310 ) which comprise subelements. The method is used for scheduling ( 415 ) first and second channels in a subframe, and comprises: dividing ( 420 ) the transmission resources for the first channel into a first set of resource groups, assigning ( 425 ) the resource groups of the first set to subelements in the subframe ( 310 ) in a predetermined fashion, assigning ( 430 ) a symbol value to all subelements ( 210 ) in the subframe ( 310 ) which have not been assigned a resource groups of the first set, dividing ( 435 ) the transmission resources for the second channel into a second set of resource groups, assigning ( 440 ) the resource groups of the second set to subelements in the subframe by means of said symbol values.

Method for Implicit Conveying of Uplink Feedback Information

Abstract: Method and apparatus for conveying feedback reports from a data receiving party (300) for data received from a data sending party (302) in a wireless connection. A plurality of feedback resources (304) assigned to different feedback information codes are allocated to the data receiving party for transmitting feedback reports. After checking whether the data was received correctly or not, the data receiving party selects a feedback resource (FR2) with a feedback information code that corresponds to one or more feedback reports on the received data. The data receiving party then sends feedback information on the selected feedback resource to the data sending party, thereby conveying the corresponding feedback information code. In this way, multiple feedback reports can be conveyed in a single feedback resource to the data sending party while still retaining single carrier properties.

Improved use of subframes in a cellular communications system

Abstract: The invention discloses a method (500) for a cellular communications system (100), in which traffic is sent in frames (200), each frame comprising a first number of subframes (201-210), 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 (515), as follows: .cndot. One part (520) which is utilized for uplink traffic, .cndot. One part (525) which is utilized for downlink traffic, .cndot. One part (530) which is utilized as a guard period, with said guard period part (525) being scheduled between the uplink and the downlink parts. The duration of at least two of said three parts (520, 525, 530) may be varied to fit the current system need.

Method and apparatus for configuring sounding signals in a wireless communication network

Abstract: The teachings presented herein propose a separation between the configuration of a sounding signal, and the initialization of the sounding signal. In other words, in at least one example embodiment proposed herein, a base station or other controlling entity separates the selection of sounding signal parameters (sounding signal configuration) and the signaling of that configuration information to a mobile terminal from the Ordering” or other initiation of sounding signal transmission. Thus, a mobile station may be sent sounding signal configuration information and subsequently be commanded (implicitly or explicitly) to begin sounding signal transmissions according to the previously provided configuration information.

Multiple sounding configurations

Abstract: More than one set of sounding signal configuration parameters are determined for the same mobile terminal. The mobile terminal uses the sets of configuration parameters to generate different sounding reference signals which can be used for different purposes such as estimating timing and channel quality. In one embodiment, a method of configuring uplink sounding transmissions by mobile terminals in a wireless communication network is characterized by determining different sets of configuration parameters for sounding signal transmissions for a given mobile terminal (200). The different sets of configuration parameters are transmitted to the mobile terminal, allowing the mobile terminal to generate different sounding signals for different uses by the wireless communication network (202).

Data block size management in a communication system utilizing hybrid automatic repeat requests with soft combining

Abstract: A first transceiver that supports hybrid Automatic Repeat Request (hybrid ARQ) functionality is operated. Initially, it is operated to transmit data blocks having a nominal maximum data block size. Mo. In response to detecting that a second transceiver does not have sufficient soft buffer memory space to store data blocks associated with an anticipated number of active hybrid ARQ processes, the transceiver is operated to transmit data blocks having a reduced data block size, M'. The anticipated number of active hybrid ARQ processes can be, for example, higher than a nominal number of active hybrid ARQ processes.

Interference randomisation of control channel elements

Abstract: A method and a radio base station for interleaving control channel data to be transmitted in a telecommunications system are described The method comprises grouping the control channel elements CCEl- CCEn into a first order of control channel symbol groups, determining a number of available symbol group positions of control channel transmission resources, adding symbol groups comprising 'dummy' values or zeros to the first order of control channel symbol groups, interleaving the first order of the control channel symbol groups resulting in an a second order, cyclic shifting the second order and mapping the cyclic shifted second order of control channel symbol groups to the control channel transmission resources

Improved scheduling in a cellular system

Abstract: In a cellular system (100), transmissions are made (410) in subframes (310) which comprise subelements. The method is used for scheduling (415) first and second channels in a subframe, and comprises: • dividing (420) the transmission resources for the first channel into a first set of resource groups, • assigning (425) the resource groups of the first set to subelements in the subframe (310) in a predetermined fashion, • assigning (430) a symbol value to all subelements (210) in the subframe (310) which have not been assigned a resource groups of the first set, • dividing (435) the transmission resources for the second channel into a second set of resource groups, • assigning (440) the resource groups of the second set to subelements in the subframe by means of said symbol values.

Uplink power control for limited power terminals

Abstract: A method for controlling the transmission power in a mobile terminal (200) in a wireless communication system in which a transmission bandwidth allocated for transmissions by the mobile terminal (200) is variable by transmission, the method comprising receiving (310) a plurality of transmission power control orders, each transmission power control order administering an adjustment in the transmission power related to a previous transmission of the mobile terminal (200); characterized in that the method further comprises: when the mobile terminal is in a state of power limitation that requires the mobile terminal to transmit at its maximum transmission power: - adjust (350) a cumulative power control value when a control order of received transmission power administers a negative adjustment in the transmission power; - ignoring a transmission power control order received when the transmission power control order received administers a positive adjustment in transmission power, so that the accumulated power control value is not adjusted when the control order of received transmission power administers a positive adjustment in transmission power; and - calculate (360) respective transmission power settings for each transmission by the mobile terminal (200) as the lower of the maximum transmission power for the mobile terminal and the transmitter output power calculated based on the bandwidth assigned for the transmission and the accumulated power control value.

Channel sounding using multiple sounding signal configurations

Abstract: More than one set of sounding signal configuration parameters are determined for the same mobile terminal. The mobile terminal uses the sets of configuration parameters to generate different sounding reference signals which can be used for different purposes such as estimating timing and channel quality. In one embodiment, a method of configuring uplink sounding transmissions by mobile terminals in a wireless communication network is characterized by determining different sets of configuration parameters for sounding signal transmissions for a given mobile terminal (200). The different sets of configuration parameters are transmitted to the mobile terminal, allowing the mobile terminal to generate different sounding signals for different uses by the wireless communication network (202).