Showing papers by "Stefan Parkvall published in 2003"

Radio resource management for a high-speed shared channel

Abstract: Radio resources like spreading codes and transmission power are optimally allocated to various different types of radio channels supported in the cell including a specialized channel like a high-speed shared channel. One or more measurements made at the base station are provided to the radio resource manager. Such measurements include other-channel power, high speed shared channel code usage, high speed shared channel transport format usage, average active load on the high speed shared channel, empty buffer, excess power, and similar parameters that relate to a high speed shared channel. One or more of these reported measurements may then be used to access, allocate, and/or regulate resources associated with the base station's cell.

Adaptive Incremental Redundancy

Abstract: We develop an information-theoretic model to explain and predict the coding gains of the incre- mental redundancy over the Chase combining scheme. From this analysis, we identify a new approach to im- prove the spectral efficiency of the conventional in- cremental redundancy scheme, which uses the same modulation and coding formats and, most notably, the same amounts of channel resources for retransmissions as those for the initial transmissions. Depending on the relative channel conditions between the transmissions, fewer incremental redundant bits than those employed in the first transmission might be enough to guaran- tee high probability of successful decoding. Hence, we propose a new scheme that adapts the modulation and coding formats according to simple feedback informa- tion to minimize unnecessary channel usage. Our sim- ulation results demonstrate system throughput gains up to 25% in certain conditions can be achieved by the proposed scheme without modifying the existing WCDMA specifications.

Adaptive incremental redundancy [WCDMA systems]

Abstract: We develop an information-theoretic model to explain and predict the coding gains of the incremental redundancy over the Chase combining scheme. From this analysis, we identify a new approach to improve the spectral efficiency of the conventional incremental redundancy scheme, which uses the same modulation and coding formats and, most notably, the same amounts of channel resources for retransmissions as those for the initial transmissions. Depending on the relative channel conditions between the transmissions, fewer incremental redundant bits than those employed in the first transmission might be enough to guarantee high probability of successful decoding. Hence, we propose a new scheme that adapts the modulation and coding formats according to simple feedback information to minimize unnecessary channel usage. Our simulation results demonstrate system throughput gains up to 25% in certain conditions can be achieved by the proposed scheme without modifying the existing WCDMA specifications.

Impacts of higher order modulation on HS-DSCH system performance

Abstract: To support high peak rates the possibility to use higher-order modulation is included in the WCDMA high-speed downlink shared channel (HS-DSCH). In an initial roll-out, higher-order modulation may not be available in all terminals and it is therefore interesting to understand to what extent enhancements offered by HS-OSCH depends on higher-order modulation. We study the impacts of higher-order modulation on HS-DSCH system performance. Our results indicate that performance gains when introducing HS-DSCH are significant, even if higher-order modulation is not available. When time dispersion is small, higher-order modulation may improve system throughput. To take advantage of higher-order modulation in environments with significant time dispersion advanced receivers structures should be considered. Furthermore, higher order modulation is found to be more sensitive to errors in the channel quality estimates.

Method and system to provide a continous wireless connection using a MS as relay

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.