Methods and arrangments for dynamically adjusting the rate of sub cell searching in coordinated multiple point transmission/reception, comp, cells
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorMuhammad Kazmi
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Abstract
The present invention relates to methods and arrangements that enable a User Equipment UE to limit the number of sub cell searches needed in a wireless communication system with Coordinated Multiple Point transmission/reception (CoMP) cells, while keeping an acceptable system performance at handovers. This is achieved by a solution where the UE does sub cell search in a candidate target CoMP cell only when the candidate target CoMP cell quality performance is within a reasonable range or when the serving CoMP cell quality performance is low.
Claims24
A method of cell search for a user equipment in a wireless communication system with Coordinated Multiple Point transmission/reception (CoMP) cells, wherein the user equipment is served by a serving CoMP cell, and wherein a CoMP cell comprises a controlling unit and at least two sub cells, each sub cell transmitting at least a CoMP cell specific synchronization signal and a sub cell specific synchronization signal, said method comprising:
- searching CoMP cells neighboring the serving CoMP cell for at least one candidate target CoMP cell,
- determining the identity of a found candidate target CoMP cell based on at least the CoMP cell specific synchronization signal,
- determining whether at least one condition, comparing a CoMP cell quality performance measure for the found candidate target CoMP cell with a threshold value, is fulfilled, and
- initiating a sub cell search at a specified rate in the found candidate target CoMP cell when the at least one condition is fulfilled.
A method of cell search for a controlling unit of a Coordinated Multiple Point transmission/reception (CoMP) cell in a wireless communication system comprising a plurality of CoMP cells, each CoMP cell comprising at least two sub cells, wherein the CoMP cell controlled by said controlling unit serves at least one user equipment, and wherein the controlling unit manages a list of candidate target CoMP celis, said method comprising transmitting to the at least one user equipment at least one threshold value that supports a determination of when a sub cell search should be initiated in a candidate target CoMP cell.
A user equipment in a wireless communication system with Coordinated Multiple Point transmission/reception (CoMP) cells, wherein the user equipment is served by a serving CoMP cell, wherein a CoMP cell comprises a controlling unit and at least two sub cells, each sub cell transmitting at least a CoMP cell specific synchronization signal and a sub cell specific synchronization signal, said user equipment comprising one or more processors configured to:
- search CoMP cells neighboring the serving CoMP cell for at least one candidate target CoMP cell,
- determine the identity of a found candidate target CoMP cell based on at least the CoMP cell specific synchronization signal,
- determine whether at least one condition, comparing a CoMP cell quality performance measure for the found candidate target CoMP cell with a threshold value, is fulfilled, and
- initiate a sub cell search at a specified rate in the found candidate target CoMP cell when the at least one condition is fulfilled.
A controlling unit of a Coordinated Multiple Point transmission/reception (CoMP) cell in a wireless communication system comprising a plurality of CoMP cells, each CoMP cell comprising at least two sub cells, wherein the CoMP cell controlled by said controlling unit serves at least one user equipment, and wherein the controlling unit comprises one or more processors configured to:
- manage a list of candidate target CoMP cells, and
- transmit to the at least one user equipment at least one threshold value that supports a determination of when a sub cell search should be initiated in a candidate target CoMP cell.
Dependencies are inferred from the claim text.