British Telecommunications Public Limited Company

Richard Thomas Mackenzie

Michael R Fitch

Anvar Tukmanov

Mo Hao

Zijian Zhang

Linglong Dai

Michael Robert Fitch

Kunzan Liu

A method in a cellular telecommunications network having a first central base station unit connecting to each of a plurality of distributed base station units, including identifying a cluster of distributed base station units within the plurality of distributed base station units, wherein each member of the cluster has a neighboring relationship with another member of the cluster that satisfies a threshold; using a first functional split in which a first set of protocol functions are implemented in the first central base station unit and a second set of protocol functions are implemented by each member of the cluster of distributed base station units; identifying a change in the membership of the cluster of distributed base station units; and, in response, causing the first central base station unit and each member of the cluster of distributed base station units to implement a second functional split in which a third set of protocol functions are implemented in the first central base station unit and a fourth set of protocol functions are implemented by each member of the cluster of distributed base station units.

Implementing functional split of protocol functions in a central base station unit

This disclosure provides a base station for a cellular network, and a method of operating the base station in the cellular network, the cellular network also including a second base station, wherein the first and second base stations include first and second oscillators providing a first and second periodic timing pulse respectively, the method including determining a relative timing offset between a first instance of the first periodic timing pulse for transmission of a frame from the first base station and a first instance of the second periodic timing pulse for transmission of a frame from the second base station; determining that the relative timing offset is changeable; and adjusting the first periodic timing pulse to maintain the relative timing offset by varying a first period between instances of the first periodic timing pulse such that the rate of change of the relative timing offset over time is reduced.

Base station, and a method of operating a base station, in a cellular telecommunications network

A mobile terminal in a wireless communications system estimates channel characteristics from transmissions of a base station comprising reference symbols arranged in a first density and distribution. In the event of an impairment in accuracy of channel estimation, the mobile terminal first applies a checking function to determine whether a base station identity conflict is present. If such a conflict is detected, it transmits a report to the base station to initiate a network channel reallocation process to remove the conflict. If no conflict is detected, the base station is instructed to initiate a function to change the density and distribution of the reference symbols. This allows a dynamic system to distinguish between different causes of poor channel quality, allowing adaptation of the transmissions of the base stations in a manner appropriate to the cause identified.

Adaptive reference signal patterns

A wireless communications network is configured to transmit signals including a plurality of data units containing reference signals for use in channel assessment by mobile stations receiving the transmissions. Topological data relating to the relative positions of each base stations in the network is used by a density adjustment function to select a distribution pattern and density of reference signals. A signal is sent to one or more user terminals, the signal comprising reference signals arranged in the selected distribution and density of plurality of data units, and including a control signal to indicate to the mobile terminal which density and distribution is in use.

Adapting reference signal density

A base station in a wireless communications network is configured to transmit signals including a plurality of data units, and selecting for transmission a signal configuration including a distribution pattern of reference signals arranged in a predetermined pattern in the data units with a predetermined density. The signal configuration also includes control data indicative of the reference signal density and distribution. A mobile terminal uses the control data to identify the reference signal density and distribution in use by the base station to which it is working or about to hand over, so that it can identify which symbols are appropriate to estimate the channel characteristics. By adapting the symbol density to local circumstances, in particular the likelihood of Doppler spreading, a more reliable acquisition of the base station can be obtained. The symbol density is reduced in the subcarriers remote from the control block, as these are less likely to be used by a mobile terminal in the circumstances in which density can be reduced.

Controlling adaptive reference signal patterns

In a wireless communications network, access points and connected mobile devices transmit data via a radio frequency spectrum channel. When a device has packets for transmission it must check the channel is available before it can transmit the data. Furthermore there is a Transmission Opportunity (TXOP) parameter which limits the maximum amount of time that a device can transmit packets before it must relinquish the channel so that other devices are not locked out. Each device in the network is capable of updating its own TXOP parameters in order to respond to changes in the level of interference and contention in the surrounding area. In this way devices can transmit for longer periods of time when contention is low, while responding to increased network contention by shortening the TXOP to ensure fair access for all other devices in the network.

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London, United Kingdom

Richard Thomas Mackenzie