WO2013167188A1

WO2013167188A1 - Method and apparatus of diversity reception

Info

Publication number: WO2013167188A1
Application number: PCT/EP2012/058629
Authority: WO
Inventors: Karri Markus Ranta-Aho; Antti Anton Toskala
Original assignee: Nokia Siemens Networks Oy
Priority date: 2012-05-10
Filing date: 2012-05-10
Publication date: 2013-11-14

Abstract

A method comprising: determining quality information relating to a channel; and selecting in dependence on said quality information one of a plurality of different receiving diversity modes, said modes comprising at least a lower diversity receiver mode and a higher diversity receiver mode. Said lower diversity mode comprises a single receiver mode and said higher diversity mode comprises a dual receiver mode.

Description

DESCRIPTION

TITLE

METHOD AND APPARATUS OF DIVERSITY RECEPTION

Some embodiments relate to a method and apparatus and in particular but not exclusively in relation to the use of diversity receivers.

A communication system can be seen as a facility that enables communication sessions between two or more entities such as fixed or mobile communication devices, base stations, servers and/or other communication nodes. A communication system and compatible communicating entities typically operate in accordance with a given standard or specification . A communication can be carried on wired or wireless carriers. In a wireless communication system at least a part of the communication between at least two stations occurs over a wireless link.

Examples of wireless systems include public land mobile networks (PLMN) such as cellular networks, satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN).

A user can access the communication system by means of an appropriate communication device. A communication device of a user is often referred to as user equipment (UE) or term inal . Typically a com mu n ication device is used for enabli ng receivi ng and transmission of communications such as speech and data. In wireless systems a communication device provides a transceiver station that can communicate with another communication device such as e.g. a base station of an access network and/or another user equipment. The communication device may access a carrier provided by a station, for example a base station, and transmit and/or receive communications on the carrier. An example of communication systems attempting to satisfy the increased demands for capacity is an architecture that is being standardized by the 3rd Generation Partnership Project (3GPP). The communication system is often referred to as Universal Mobile Telecommunications System (UMTS) radio-access technology with the enhancements for High Speed Packet Access (HSPA) which improves the downlink and uplink transmission (H S D PA, H S U PA), a nd the l on g-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The HSPA and LTE enhancements aim to achieve various improvements, for example reduced latency, higher user data rates, improved system capacity and coverage, reduced cost for the operator and so on. A further development of the LTE is often referred to as LTE-Advanced. The various development stages of the 3GPP LTE and HSPA specifications are referred to as releases.

In mobile communications, if two or more receive antennas are used, better signal-to- noise ratios may be achieved. This may lead to higher achievable data rates and/or an improved signal robustness near the edges of cells. Thus, dual receiver architectures are becoming more popular. For example, such architectures are being used in wireless broadband USB dongles and high-end smart phones. Some standards, such as the LTE standard, prevent a single receiver device implementation.

SUMMARY

According to a first aspect there is provided a method comprising: determining quality information relating to a channel; and selecting in dependence on said quality information one of a plurality of different receiving diversity modes, said modes comprising at least a lower diversity receiver mode and a higher diversity receiver mode.

The quality information may comprise channel quality information.

The method may comprise comparing said quality information to a threshold. The method may comprise selecting a lower diversity mode when the quality information indicates that the channel quality is relatively high . The method may comprise receiving receiving diversity mode information from a network node for controlling said receiving mode.

The lower diversity mode may comprise a single receiver mode. The higher diversity mode may comprise a dual receiver mode.

The mode information may comprise time information for at least one of said receiving modes. The time information may comprise at least one of when at least one of said receiving modes is to be used, for how long at least one of said receiving modes is to be used; and a period of inactivity after which a change is to be made to said receiving mode.

The mode information may comprise traffic information for at least one of said receiving modes. The traffic information may comprise one or more of types of packet, service, traffic type, priority level, and channel.

The receiving mode information may comprises threshold information, said threshold defining when a change in diversity mode is permitted.

The threshold information may comprise channel quality threshold information.

The mode information may comprise a command.

The method may comprise switching from a first diversity mode to a second diversity mode in response to receiving at least one communication for which a the second diversity mode is more appropriate. The method may comprise receiving switching information for defining a rule for switching from said first diversity mode to the second diversity mode.

The method may comprise providing channel quality information to said network node, said channel quality information being based on measurements made by only the at least one receiver used in a low diversity mode.

There is provided according to a second aspect a method comprising receiving receiving mode information from a network node for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and receiving a communication from said network node, wherein a receiving mode for said communication is selected in dependence on said receiving mode information.

The method may comprise causing receiver mode capability information to be sent to said network node, said capability information indicating supported receiving modes.

The method may comprise receiving an acknowledgment from said network node of said capability information.

The mode information may comprise time information for at least one of said receiving modes. The time information may comprise at least one of when at least one of said receiving modes is to be used, for how long at least one of said receiving modes is to be used; and a period of inactivity after which a change is to be made to said receiving mode. The mode information may comprise traffic information for at least one of said receiving modes. The traffic information may comprise one or more of types of packet, service, traffic type, priority level, and channel.

The threshold information may comprise channel quality threshold information.

The mode information may comprise a command.

The method may comprise switching from a first diversity mode to a second diversity mode in response to receiving at least one communication for which a the second diversity mode is more appropriate.

The method may comprise receiving switching information for defining a rule for switching from said first diversity mode to the second diversity mode.

There is provided according to a third aspect a method comprising: causing receiving mode information to be sent to a user device for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and causing a communication to be sent to said user equipment from said network node, wherein at least one transmission characteristic is dependent on an associated receiving mode. The at least one transmission characteristic may comprises power.

There is provided according to a fourth aspect a method comprising: receiving channel quality information from a user device, said user device comprising having a plurality of diversity receiver modes, said channel quality information being based on measurements made by one or more receivers of said user device used in a lower receiver diversity mode; determining a power to be used for a communication to be sent to said user device, said communication to be received in a higher receiver diversity mode, in dependence on said received channel quality information and compensation applied to said received channel quality information.

A computer program product may be configured to perform at least one of the methods.

There is provided according to a fifth aspect an apparatus comprising at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determine quality information relating to a channel; and select in dependence on said quality information one of a plurality of different receiving diversity modes, said modes comprising at least a lower diversity receiver mode and a higher diversity receiver mode.

The quality information may comprise channel quality information.

The apparatus may be configured to compare said quality information to a threshold. The apparatus may be configured to select a lower diversity mode when the quality information indicates that the channel quality is relatively high. The apparatus may be configured to receive receiving diversity mode information from a network node for controlling said receiving mode. The lower diversity mode may comprise a single receiver mode. The higher diversity mode may comprise a dual receiver mode.

The threshold information may comprise channel quality threshold information.

The mode information may comprise a command.

The apparatus may be configured to switch from a first diversity mode to a second diversity mode in response to receiving at least one communication for which a the second diversity mode is more appropriate.

The apparatus may be configured to receive switching information for defining a rule for switching from said first diversity mode to the second diversity mode. The apparatus may be configured to provide channel quality information to said network node, said channel quality information being based on measurements made by only the at least one receiver used in a low diversity mode.

There is provided according to a sixth aspect an apparatus comprising determining means for determining quality information relating to a channel; and selecting means for selecting in dependence on said quality information one of a plurality of different receiving diversity modes, said modes comprising at least a lower diversity receiver mode and a higher diversity receiver mode.

There is provided according to a seventh aspect an apparatus comprising at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: receive receiving mode information from a network node for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and receive a communication from said network node, wherein a receivi ng mode for said com mu n ication is selected i n dependence on said receiving mode information.

The apparatus may be configured to cause receiver mode capability information to be sent to said network node, said capability information indicating supported receiving modes.

The apparatus may be configured to receive an acknowledgment from said network node of said capability information.

The receiving mode information may comprise threshold information , said threshold defining when a change in diversity mode is permitted.

The threshold information may comprise channel quality threshold information.

The mode information may comprise a command.

The apparatus may be configured to receive switching information for defining a rule for switching from said first diversity mode to the second diversity mode.

The apparatus may be configured to provide channel quality information to said network node, said channel quality information being based on measurements made by only the at least one receiver used in a low diversity mode.

There is provided according to an eighth aspect receiving means for receiving receiving mode information from a network node for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and receiving a communication from said network node, wherein a receiving mode for said communication is selected in dependence on said receiving mode information.

There is provided according to a ninth aspect comprising an apparatus at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: cause receiving mode information to be sent to a user device for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and cause a communication to be sent to said user equipment from said network node, wherein at least one transmission characteristic is dependent on an associated receiving mode.

The at least one transmission characteristic may comprises power.

There is provided according to a tenth aspect processing means for causing receiving mode information to be sent to a user device for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and causing a communication to be sent to said user equipment from said network node, wherein at least one transmission characteristic is dependent on an associated receiving mode.

There is provided according to an eleventh aspect an apparatus comprising at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: receive channel quality information from a user device, said user device comprising having a plurality of diversity receiver modes, said channel quality information being based on measurements made by one or more receivers of said user device used in a lower receiver diversity mode; and a processor configured to determine a power to be used for a communication to be sent to said user device, said communication to be received in a higher receiver diversity mode, in dependence on said received channel quality information and compensation applied to said received channel quality information.

There is provided according to a twelfth aspect receiving means for receiving channel quality information from a user device, said user device comprising having a plurality of diversity receiver modes, said channel quality information being based on measurements made by one or more receivers of said user device used in a lower receiver diversity mode; and determining means for determining a power to be used for a communication to be sent to said user device, said commu nication to be received in a higher receiver d iversity mode, i n depen dence on said received ch an n el q ual ity i nformation a nd compensation applied to said received channel quality information.

A computer program comprising program code means adapted to perform the herein described methods may also be provided . I n accordance with further embodiments apparatus and/or com puter program prod uct that can be embod ied on a com puter readable medium for providing at least one of the above methods is provided.

It should be appreciated that any feature of any aspect may be combined with any other feature of any other aspect.

Embodi ments wil l now be descri bed in further detail , by way of exam ple on ly, with reference to the following examples and accompanying drawings, in which:

Figu re 1 shows a schematic d iagram of a comm un ication system where the invention may be embodied; Figu re 2 shows a schematic diagram of a mobile device implementing certain embodiments;

Figure 3 shows a schematic diagram of a base station;

Figure 4 shows a signal flow in one embodiment; and

Figures 5a to 5e which shows various different modes of user equipment; and Figure 6 shows a signal flow in another embodiment.

In the following certain exemplifying embodiments are explained with reference to a wireless or mobile communication system serving mobile communication devices. Before explaining in detail the exemplifying embodiments, certain general principles of wireless communications and radio link control are briefly explained with reference to Figures 1 to 3 to assist in understanding the technical detail underlying the described examples.

A n on-limiting example of communication system architectures is Universal Mobile Telecommunications System (UMTS) standardized by the 3rd Generation Partnership Project (3GPP). 3GPP base stations are known as Node Bs (for UMTS) and enhanced Node Bs (for 3GPP Long Term Evolution , LTE). The base station typically provide features such as user plane Radio Link Control/Medium Access Control/Physical layer protocol (RLC/MAC/PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other examples of radio access system include those provided by base stations of systems that are based on technologies such as wireless local area network (WLAN) and/or WiMax (Worldwide I nteroperability for Microwave Access).

Mobile communication devices 1 can be provided with wireless access via base stations or similar wireless transmitter and/or receiver nodes providing radio service areas or cells. Figure 1 shows two bases stations 2 and 4 proving cell 3 and 5, respectively. A mobile com mu n ication device 1 may be located i n the service areas of d ifferent cells, communicate with more than one cell and be handed over from a cell to another. The base station nodes can be connected to a core communications network via appropriate gateways and/or backhaul systems. It is noted that the base stations and mobile devices are only schematically shown for illustration purposes in Figure 1 , and that the number and type of these can vary considerably from that shown. Base stations are typically controlled by at least one appropriate controller apparatus so as to enable operation thereof and management of mobile communication devices in communication with the base stations. The control apparatus can be interconnected with other control entities. The control apparatus can be configured to execute an appropriate software code to provide the control functions. The control apparatus and functions may be distributed between a plurality of control units. Two or more base stations may be controlled a control apparatus 6.

A possible mobile device for communications with the base stations is often referred to as user equipment (UE) or terminal. A mobile device for implementing the embodiments may be provided by any device capable of sending radio signals to and/or receiving radio signals from multiple cells. Non-limiting examples include a mobile station (MS) such as a mobile phone or what is known as a 'smart phone', a portable computer provided with a wireless interface card or other wireless interface facility, personal data assistant (PDA) provided with wireless communication capabilities, or any combinations of these or the like. A mobile device may provide, for example, commun ication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on . Users may thus be offered and provided numerous services via their devices. Non- l i m i ti n g exa m p l es of th ese se rvi ces i n cl u d e two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. User may also be provided broadcast or multicast data . Non-limiting exam ples of the content incl ude down loads, television and radio programs, videos, advertisements, various alerts and other information.

A mobile device may receive and transmit signals over an air interface with multiple base stations via an appropriate transceiver apparatus. In Figure 2 transceiver apparatus of a mobile device 20 is designated schematically by first and second blocks 26 and 27. The transceiver blocks 26 m ay be provided for exam ple by mean s of a rad io pa rt a nd associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device. In some embodiments, the first transceiver block 26 is associated with a first antenna and the second transceiver block is associated with a second antenna. When both the receiver blocks are receiving, diversity is obtained. As will be described in more detail , two modes may be provided . I n one mode, both receiver blocks are receiving and in another mode only one of the receiver blocks is receiving.

A mobile device is also provided with at least one data processing entity 21 , at least one memory 22, and other possible components 23 for use in software and hardware aided execution of tasks it is d esi gn ed to perform , i ncl u d i n g control of access to a n d communications with access systems and other communication devices. The data processi ng , storage a nd oth er relevant control apparatus can be provid ed on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 24.

The user may control the operation of the mobile device by means of a suitable user i nterface su ch as key pad 25 , voice com m an d s , touch sen sitive screen or pad , combinations thereof or the like. A display 28, a speaker and a microphone can be also provided . Furthermore, a mobile comm u nication device may com prise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

A wireless communication device, such as a base station and/or a mobile station, can be provided for example with two or more receivers facilitating receive diversity for enhanced aggregate receiver sensitivity, or a M ultiple I nput / M ultiple Output (M I MO) anten na system for enabling multi-stream communications. Receiver (Rx) diversity and MI MO arrangements as such are known. Rx diversity uses multiple antennas at the receiver and MI MO systems use multiple antennas at the transmitter and receiver along with advanced digital signal processing to improve link quality and capacity. More data can be received and/or sent where there are more antenna elements.

Reference is made to Figu re 3 wh ich shows a base station 1 05. The base station comprises at least one memory 401 and at least one data processing unit 402 and 403. The base station is provided with a first interface 404 for interfacing with the RN C or another controller. The base station is provided with a second interface 405 which is a wireless interface for interfacing with user equipment.

In user devices, operating two receive antennas increases the instantaneous power drawn from the battery. However, this may be offset by a better receiver sensitivity translating to higher achievable data rates or better service coverage. Higher data rates may in turn shorten the time needed for a wireless broadband transaction. A shorter transaction time may reduce the overall energy consumed, in some embodiments. Accordingly, the overall impact of using two receive antennas may reduce the overall energy consumed. When the device is being used for conversational or streaming services such as a regular voice call , a user may not benefit from the higher achievable data rates and the transaction time (voice call duration) is not shortened by using two or more antennas. In WCDMA/HSPA networks, this has led to the introduction of devices which use two antennas to receive packet traffic, such as HSPA traffic and only a single antenna when receiving voice traffic via the DCH. This is to try to get the best battery life (device talk time) for voice calls and the best performance for data transactions.

With the current LTE requirements, voice or the like calls are required to be received on two antennas. Single receive operation is not permitted. This may lead to the reduction in available talk times or the devices need to resort to non-standard practices such as shutting down the other receiver. Where user equipment shuts down the second receiver, this can cause complications as this is not known by the network and may result in issues such as link robustness and overall service availability in networks deployed assuming two receive antennas.

In some embodiments, a network configurable channel quality related threshold may be provided. For example, if the channel quality is above the threshold, the user equipment would be allowed to disable the receiver diversity. In other words, the user equipment would be able to use a single antenna only.

The channel quality related threshold may be based on a channel quality indicator (CQI). In alternative embodiments, any other suitable channel quality information may be used.

If the channel quality is above the required threshold, the user equipment could be explicitly instructed to use a single receiver. Alternatively or additionally, the user equipment may make the decision as to whether or not to use a single antenna based on the service type. For example, if the quality of the channel is above the threshold and the service is a voice, or other service of relatively constant bit rate, then the user equipment may use a single antenna. In other embodiments, the user equipment may determine, once the channel quality is above a threshold, whether to use one or more antenna based on additionally or alternatively the associated logical channel and/or the priority of the service. The parameters which control for example the channel quality threshold, and/or the circumstances in which a single antenna is to be used may be defined in the radio resource control (RRC) protocol. The behaviour may be defined in L1 , L2 and/or RRC definitions. The parameters defining the behaviour may include defining when data is received frequently in the single receiver time interval in order to switch to more receiver operation to improve user experience, or may include parameters defining when data is received rarely in multiple receiver time interval in order to switch back from multiple receiver operation to improve user experience. The parameters may include and depend on the obtained throughput at a receiver of U E or at more receivers of the U E, the theoretical maximum throughput on one or more receivers of U E, the number of retransmissions until successful transmission, and the error rate of transmissions during a period of time.

In some embodiments, there may be network configurable time instance in which the user equipment would use receiver diversity periodically. This may allow the network to schedule intermittently arriving voice packets and/or arbitrarily arriving robustness critical signalling packets on those known receiver diversity time intervals. At other times, the user equipment may be still reachable as a single antenna device with reduced receiver sensitivity.

For example, the user equipment may be provided with parameters indicating one or more of when, how often and for how long the user equipment should apply one or both of the operating modes. The operating modes may be a single receiver mode and a two receiver mode. These parameters may be defined in for example the radio resource protocol. Again, the behaviour may be included in L1 , L2 and/or RRC definitions.

With voice traffic, typically a new voice frame arrives once every 20 ms during an active speech phase. The transmission over the air takes one transmission time interval and possible subsequent retransmissions. In some cases, the transmission time interval may be 2 milliseconds for HSDPA and 1 ms for LTE. In one embodiment, a natural phasing would be to have for example a 20 ms cycle and a window of at least one TTI for the user equipment to operate in a two receiver mode. Having longer than one TTI allows for a longer scheduling window in the node B to transmit knowing the UE is receiving with two receivers, and this helps maximising the network capacity. Having a window of just one TTI would help maximising the UE battery saving, but it would either force the Node B to transmit the voice frame at a fixed time instant, not leaving any scheduling flexibility, or the Node B would alternatively sometimes need to transmit the voice frame while the UE is using just one receiver. The setting of the dual-receiver mode window length may be a trade-off between the two. In other words, in the 20 ms cycle (the arrival time of voice frames), at least for the time interval it takes to transmit the voice frame over the air, the U E is using both receivers and thus able to receive data with improved sensitivity as compared to single receiver operation, and the rest of the 20 ms cycle the UE is using just one receiver, still being able to receive transmissions, but with reduced sensitivity as compared to dual receiver operation, but with reduced battery consumption. Switching from multiple receiver operation to fewer receiver operation eg., from 6 receiver operation to 2 receiver operation , is achieved by deactivating one or more receivers and the processing units related to the receiver. The processing units related to a deactivated receiver may include an antenna which receives and transmits radio signals and exchanges them with the receiver, a decoder which decodes received signals and provides decoded signals to further processing units, a re-transmission unit which processes re-transmissions of unsuccessfully received or unsuccessfully decoded signals, a combination unit which combines received signals or decoded signals of a receiver, a further combination unit which combines the received signals or decoded signals of a receiver with signals of a further receiver which would increase sensitivity if activated and in operation.

In some embodiments, the user equipment may revert back to using receiver diversity based on data traffic received, e.g. if the user equipment starts receiving higher data rates or other types of traffic than the one for which the battery saving benefits of a single receiver operation would be obtained. In some embodiments, the user equipment may revert to the diversity mode if the user equipment starts receiving data frequently in the single receiver time interval. In some embodiments, this may be implemented by providing rules for the user equipment operation, in for example the user equipment. These rules which define the criteria which would require the user equipment to revert back to using receiver diversity. The rules may define for example that the user equipment should revert to the diversity mode when at least one of receiving a certain type of packet, there is a certain type of service, there is a certain type of traffic, there is a certain type of priority level, and/or there is a certain logical channel associated with the received packet.

The user equipment may be configured to revert to a default mode after the traffic which caused the user equipment to change mode is no longer present. The default mode may, in some embodiments, be the single receiver mode. In alternative embodiments, the default mode may be the diversity mode. A data or service inactivity timer may be provided. Only after the expiry of that timer will the user equipment revert to the default mode. In other words, the traffic which caused the switching from the default mode to the other mode should be absent for a period of time defined by the inactivity timer, before reverting to the default mode. I n some embodiments, the user equipment maybe configured to return to the default mode after having not received one or more of a certain type of packet, a certain service, a certain traffic type, a certain priority level type of traffic, or logical channel, for a period of time defined by the inactivity timer.

I n some embodiments the network node has information relating to when the user equipment is operating in the single receiver mode or the diversity mode, the network is able to control the signal strength which is used when transmitting to the user equipment. For example, the network node may reduce the signal strength when the user equipment is in its diversity mode.

In some embodiments, the information about channel quality which is provided by the user equipment may relate to one or both of the single and diversity modes. The network node may, in some embodiments, have some information indicating the mode with which the channel quality information is associated.

In some embodiments, the Channel Quality information (CQI) feedback from the user equipment to the network is based on the single antenna receiver expected performance, even if part of the time diversity receiver is used. During the scheduling intervals when the receiver diversity is available the network node may use an offset for the CQI to enable the use of a suitable modulation and coding rate and number of data streams in case M I MO is available. In some embodiments, the offset may be an added offset, a subtracted offset or any other type of offset compensation.

The network node may be a base station, nodeB or radio network controller.

In some embodiments, a base station may be configured to provide orders that can be used to deactivate and/or reactivate the above described functionality. For example, in WCDMA HSPA, the base station may provide an HS-SCCH (high speed shared control channel) order.

Alternatively, in LTE the base station may provide a PDCCH (physical down link control channel) and/or MAC (medium access control) order.

Some embodiments may be used particularly for the implementation of voice over HSDPA to enable the usage of receiver diversity and adding robustness for voice over HSDPA. For connections and traffic such as voice connections, battery saving benefits may be provided by using the single antenna mode most of the time.

In step S1 , the user equipment 400 is configured to send in step S1 , a user equipment capability notification to a network node 402. The network node may be a base station or a radio resource controller. The radio resource controller may be provided in the base station or in a higher level node. The user equipment capability notification may include information indicating that single/plurality receiver operation is supported. The user equipment capability notification may include any other relevant information about the capability of the user equipment required by the network node or radio resource control.

This notification from the U E may be sent at any suitable time. For example, this information may be provided when a connection is initiated with the network node.

In step S2, the network node or radio resource controller 402 is configured to receive the notification and store the notification . The network node may also be configured to evaluate the capability notification. This may be done when the information is received from the user equipment or may be done at a later stage when the capability of supporting single-plurality receiver operation is an issue.

In step S3, the network node or radio resource controller is configured to send a response to the user equipment 400 indicating that the user equipment capability notification has been successfully received. In some embodiments, step S3 may be omitted. In some embodiments, this acknowledgement may be provided with other information from the network node or radio resource controller.

In step S4, the network node 402 selects the radio resources depending on the reported radio conditions and/or user traffic type. I n alternative embodiments, alternative or additional criteria may be considered. The network node may select if the user equipment is to operate in a single receiver operation mode or a plurality receiver operation mode. In some embodiments, this may be done in dependence on the selected radio resources and/or in dependence on for example the reported radio conditions and/or user traffic type

The network node instructs the user equipment and related network nodes cooperate with the selected radio parameters. In the case of the instruction for the user equipment, this is represented by step S5 where the user equipment radio link assignment request is sent to the user eq uipment. Th is will include i nformation relati ng to the radio resou rce configuration for single or plurality receiver operation.

I n step S6, the user equipment is configured to provide a user equipment radio link assignment response indicating an outcome of the assignment request received from the network node in step S5. This will indicate if the UE is able to operate with the request receiver operation.

Reference is made to Figure 6 which shows an simplified alternative to the method of Figure 4. In step E1 , the user equipment sends an indication to the network node that the

UE is capable of operating in two or more diversity modes. In step E2, the network node sends link configuration to the UE. The link configuration may comprise information or one or more parameters controlling the diversity mode of the user equipment. The U E will then operate in dependence on the information or one or more parameters received from the network node.

Reference is now made to Figure 5 which shows different modes. Some UE may have all of the modes shown. Other UE may only have one of the modes shown. Some U E may have two or more of the modes shown.

In the mode shown in Figure 5a, the U E is capable of receiving in a higher diversity mode in step T1 . I n step T2 , the U E wi ll receive in a lower d iversity mode if one or more conditions such as previously described are satisfied. In step T3, the U E will receive in a higher diversity mode if one or more of the conditions previously described are satisfied.

In the mode shown in Figure 5b, the U E is capable of receiving in a higher diversity mode in step A1 . I n step A2, the U E will receive in a lower diversity mode if the link quality is above a threshold. I n step A3, the U E will receive in a higher diversity mode if the link quality is below a threshold. Depending on the link quality, one of step A2 or A3 will follow step A1 .

In the mode shown in Figure 5c, the UE is capable of receiving in a higher diversity mode in step B1 . In step B2, the U E will receive in a lower diversity mode if a received data rate or data volume is below a threshold. I n step B3, the U E will receive a higher diversity mode if received data rate or data volume is above a threshold.

In the mode shown in Figure 5d, the UE is capable of receiving in a higher diversity mode in step C1 . I n step C2, the U E will periodically receive in a lower diversity mode. In step C3, the U E will receive in a higher d iversity mode only if one or more conditions are satisfied. In the mode shown in Figure 5e, the UE is capable of receiving in a higher diversity mode in step D1 . In step D2, the UE will report the channel quality corresponding to the lower diversity mode.

In the described embodiments, the communication device has two receiver modes. The two receiver modes may be a higher receiver diversity mode and a lower receiver diversity mode. The number of receivers active in the lower diversity mode will be less than the number of receivers active in the higher diversity mode. In the previously described embodiments, the number of receivers in the lower diversity mode is one. I n other embodiments, the number of receivers in the lower diversity mode may be greater than one. In the previously described embodiments, the number of receivers in the higher diversity mode is two. In other embodiments, the number of receivers in the higher diversity mode may be greater than two.

In some embodiments more than two different diversity modes may be provided.

It is noted that whilst embodiments have been described using an UMTS based system as an example, similar principles can be applied to any other communication system or indeed to further developments with UMTS. Thus, instead of the U MTS and HSPA, the invention may be applied to other cellular standards and technologies as well. Also, instead of carriers provided by base stations at least one of the carriers may be provided by a communication device such as mobile user equipment. For example, this may be the case in application where no fixed equipment provided but a communication system is provided by means of a plurality of user equipment, for example in adhoc networks. Therefore, although certain embodiments were described above by way of example with reference to certain exemplifying architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

The required data processing apparatus and functions of a base station apparatus, a communication device and any other appropriate apparatus may be provided by means of one or more data processors. The described functions at each end may be provided by separate processors or by an integrated processor. The data processors may be of any type suitable to the local technical environment, and may include one or more of general pu rpose com puters, special pu rpose com puters, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi core processor architecture, as non- limiting examples. The data processing may be distributed across several data processing modules. A data processor may be provided by means of, for example, at least one chip. Appropriate memory capacity can also be provided in the relevant devices. The memory or memories may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, tech n iq ues or methods descri bed herein may be im plemented in , as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the spirit and scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more of any of the other embodiments previously discussed.

Claims

1 . A method comprising: determining quality information relating to a channel; and selecting in dependence on said quality information one of a plurality of different receiving diversity modes, said modes comprising at least a lower diversity receiver mode and a higher diversity receiver mode.

2. A method as clai med i n clai m 1 , wherein said quality information comprises channel quality information.

3. A method as claimed in claim 1 or 2, comprising comparing said quality information to a threshold.

4. A method as claimed in any preceding claim, comprising selecting a lower diversity mode when the quality information indicates that the channel quality is relatively high.

5. A method as claimed in any preceding claim, comprising receiving receiving diversity mode information from a network node for controlling said receiving mode.

6. A method comprising: receiving receiving mode information from a network node for controll i ng a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and receiving a communication from said network node, wherein a receiving mode for said communication is selected in dependence on said receiving mode information.

7. A method as claimed in any preceding claim, wherein said lower diversity mode comprises a single receiver mode.

8. A method as claimed in any preceding claim, wherein said higher diversity mode comprises a dual receiver mode.

9. A method as claimed in claim in any of cla i m s 5 to 8, wherein said mode information comprises time information for at least one of said receiving modes.

10. A method as claimed in claim 9, wherein said time information comprises at least one of when at least one of said receiving modes is to be used, for how long at least one of said receiving modes is to be used; and a period of inactivity after which a change is to be made to said receiving mode.

1 1 . A method as claimed in any of claims 5 to 1 0, wherein said mode information comprises traffic information for at least one of said receiving modes.

12. A method as claimed in claim 1 1 , wherein said traffic information comprising one or more of types of packet, service, traffic type, priority level, and channel.

13. A method as claimed in any of claims 5 to 12, wherein said mode information comprises a command.

14. A method as claimed in any preceding claim, comprising switching from a first diversity mode to a second d iversity mode in response to receiving at least one communication for which a the second diversity mode is more appropriate.

15. A method as claimed in any preceding claim, comprising providing channel quality information to said network node, said chan nel q ual ity information being based on measurements made by only the at least one receiver used in a low diversity mode.

16. A method comprising: causing receiving mode information to be sent to a user device for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and causing a communication to be sent to said user equipment from said network node, wherein at least one transmission characteristic is dependent on an associated receiving mode.

17. A method comprising: receiving channel quality information from a u ser devi ce , sai d user devi ce comprising having a plurality of diversity receiver modes, said channel quality information being based on measurements made by one or more receivers of said user device used in a lower receiver diversity mode; determ ini ng a power to be used for a commu nication to be sent to said user device, said comm un ication to be received i n a h igher receiver d iversity mode, i n dependence on said received channel quality information and compensation applied to said received channel quality information.

18. A computer program product configured to perform the method of any preceding claim.

19. An apparatus comprising: at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: determine quality information relating to a channel; and select in dependence on said quality information one of a plurality of different receiving diversity modes, said modes comprising at least a lower diversity receiver mode and a higher diversity receiver mode.

20. An apparatus comprising: at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: receive receiving mode information from a network node for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and receive a communication from said network node, wherein a receiving mode for said commu nication is selected in dependence on said receiving mode information.

21 . An apparatus comprising: at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: cause receiving mode information to be sent to a user device for controlling a receiving mode, said receiving mode comprising a lower diversity mode and a higher diversity mode; and cause a communication to be sent to sa id user eq u i pment from said network node, wherein at least one transm ission characteristic is dependent on an associated receiving mode.

22. An apparatus comprising: at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: receive channel quality information from a user device, said user device comprising having a plurality of diversity receiver modes, said channel quality information being based on measurements made by one or more receivers of said user device used in a lower receiver diversity mode; and determine a power to be used for a communication to be sent to said user device, said comm u n ication to be received i n a h igher receiver d iversity mode, in dependence on said received channel quality information and compensation applied to said received channel quality information.