Reconfiguration of active component carrier set in multi-carrier wireless systems

#The present invention is related to wireless communications systems, and in particular is related to the operation of mobile stations and base stations in a multi-carrier wireless system, in which data can be transmitted to or from a mobile station using two or more distinct, separately modulated, carrier frequencies.

#Forthcoming cellular system standards, such as the so-called “Long-Term Evolution” (LTE) systems developed by participants in the 3<rd>-Generation Partnership Project (3GPP), will provide a much larger degree of flexibility than currently operating wireless networks. In particular, systems deployed according to Release 10 of the 3GPP LTE specifications will be better able than existing systems to exploit the full potential of the new technologies introduced in LTE, both in terms of system and per-user throughput, and will be better suited for co-existence and deployment in legacy bands.

#A mobile station (a user equipment, or UE, in 3GPP terminology) designed for such future standards will generally be required to support a wide range of bandwidths, in many cases aggregated within or over multiple bands. Carrier aggregation, in which two or more separately modulated carrier signals in distinct frequency bands are simultaneously used to carry uplink or downlink traffic for a given mobile station, may be viewed as a scheme for providing flexible bandwidth configuration on a sub-frame basis. With this dynamic re-allocation of potentially large chunks of bandwidth, future systems will be able to quickly respond to users' varying needs for data transmission throughput.

#FIG. 1 is a timing diagram illustrating effects of a component-carrier configuration change on a wireless receiver.

#FIG. 2 is another timing diagram illustrating the use of a guard interval according to some embodiments of the present invention.

#FIG. 3 illustrates functional elements of an exemplary base station and an exemplary wireless receiver.

#The introduction to wireless systems of carrier aggregation, i.e., multi-carrier operation, calls for mobile stations having the flexibility to reconfigure their radio transceiver resources depending on which component carriers (CC) are active (i.e., actually or potentially carrying control and/or traffic data for that mobile station) at a given point in time. A brute-force transceiver design might have multiple and independent transceiver entities, e.g., one for each carrier or perhaps one for each set of contiguous carriers. More elaborate receiver and transmitter architectures that are specifically tailored for carrier aggregation may be unable to reconfigure on a per-CC basis, because some transceiver parts are shared for the processing of several carriers. However, still more sophisticated designs may allow the selective activation, deactivation, or reconfiguration of various receiver and/or transmitter components in response to dynamic changes in the configuration of component carriers, to minimize power consumption.

#A potential problem with multi-carrier receiver/transmitter designs stems from the fact that events such as power-up, power-down, or reconfiguration of some blocks of a transceiver may not be acceptable while data is being received or transmitted on any carrier. Such events, even if they are carried out with respect to blocks that are not currently being used for transmission and/or reception, may nevertheless interfere with the operation of active blocks.

#One reason for this is that such events can generate transient responses (voltage and current spikes, voltage offsets, etc.) that may be coupled to devices and nodes of active blocks through various means, including, but not limited to, voltage/current supply wires and traces, capacitive and inductive coupling, substrate coupling, and thermal coupling. Coupling of these transient responses to active functional blocks of the transceiver may interfere with ongoing transmission and reception. This interference may be direct, e.g., via coupling to nodes and devices operating on the desired signals, or indirect, e.g., via coupling to nodes and devices that control the behavior (gain, transfer function, oscillation frequency etc.) of active functional blocks, or both.