Abstract: Transmissions over a unidirectional optical fiber coupling multiple nodes are compensated for temperature-induced effects. A round-trip delay time is determined for a signal sent from a first node to travel around the unidirectional optical fiber loop and be received back at the first node. That measured round-trip delay time is then used to account for temperature-induced effects on signal transmissions over the unidirectional optical fiber loop. This temperature compensation is particularly beneficial in applications that require a high level of timing accuracy.

Abstract: Remote frequency synchronization is achieved between two or more nodes in a packet-switched network using differential timestamps. A line is fit to multiple differential time values using a minimum delay principle. Frequency synchronization and/or absolute time synchronization between the two nodes may be achieved using one or both of uplink and downlink differential time values and fitting one or both of first and second lines to differential time values by different means of the minimum delay principle.

Abstract: The invention relates to a cellular communication system based on a central main unit, a primary-cell communication unit connected to the central main unit, and a number of secondary-cell communication units. Each secondary-cell unit is connected to the primary-cell unit via a respective wireless optical link. The secondary-cell communication units are preferably remote radio units in a distributed radio base system, where each remote radio unit forms a distributed radio base station together with the central main unit. The wireless optical link quality is measured to detect reduced link availability. The invention compensates for insufficient link availability by providing adequate radio coverage from another communication unit within the cellular system and re-directing the radio traffic to that communication unit. Adequate radio coverage from another communication unit within the cellular system and re-directing the radio traffic to that communication unit.

Abstract: Transmissions over a unidirectional optical fiber coupling multiple nodes are compensated for temperature-induced effects. A round-trip delay time is determined for a signal sent from a first node to travel around the unidirectional optical fiber loop and be received back at the first node. That measured round-trip delay time is then used to account for temperature-induced effects on signal transmissions over the unidirectional optical fiber loop. This temperature compensation is particularly beneficial in applications that require a high level of timing accuracy.

Abstract: The invention relates to a cellular communication system based on a central main unit, a primary-cell communication unit connected to the central main unit, and a number of secondary-cell communication units. Each secondary-cell unit is connected to the primary-cell unit via a respective wireless optical link. The secondary-cell communication units are preferably remote radio units in a distributed radio base system, where each remote radio unit forms a distributed radio base station together with the central main unit. The wireless optical link quality is measured to detect reduced link availability. The invention compensates for insufficient link availability by providing adequate radio coverage from another communication unit within the cellular system and re-directing the radio traffic to that communication unit. Adequate radio coverage from another communication unit within the cellular system and re-directing the radio traffic to that communication unit.

Abstract: Remote frequency synchronization is achieved between two or more nodes in a packet-switched network using differential timestamps. A line is fit to multiple differential time values using a minimum delay principle. Frequency synchronization and/or absolute time synchronization between the two nodes may be achieved using one or both of uplink and downlink differential time values and fitting one or both of first and second lines to differential time values by different means of the minimum delay principle.