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AssigneeAlcatel
InventorsJan Lieven Bert De Groote, Ingrid Zulma Benoit Van De Voorde
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A time slot management method for use in a time division multiple access network. The time division multiple access network includes a main station (MS) coupled to each of a plurality of substations (S1, S2, S3, . . . , S15, S16) via the cascade connection of a common transmission link (Lc) and an individual user link (L1, L2, L3, . . . , L15, L16). The management method includes broadcasting substation identities (TEA1, TEA12, TEA16, TEA3, TEA7, . . . ) in downstream information packets from the main station (MS) to the plurality of substations (S1, S2, S3, . . . , S15, S16) to allow each one of the plurality of substations (S1, S2, S3, . . . , S15, S16) upon detection of its own substation identity to transfer a predetermined amount of upstream information packets in predetermined upstream timeslots to the main station (MS). The time slot management method additionally includes embedding at least part of the substation identities (TEA12, TEA3, TEA7, . . . ) in a physical layer operation and maintenance part. The physical layer operation and maintenance part is a predefined part of one of the downstream information packets broadcasted from the main station (MS) to the plurality of substations (S1, S2, S3, . . . , S15, S16) to transport operation and maintenance information packets related to operation and maintenance functions. Such a physical layer operation and maintenance part can be a physical layer operation and maintenance cell (PLOAM).
A time slot management method for use in a time division multiple access network which includes a main station (MS) coupled to each of a plurality of substations (S1, S2, S3, . . . , S15, S16) via the cascade connection of a common transmission link (Lc) and an individual user link (L1, L2, L3, . . . , L15, L16), said management method including broadcasting substation identities (TEA1, TEA12, TEA16, TEA3, TEA7, . . . ) in downstream information packets from said main station (MS) to said plurality of substations (S1, S2, S3, . . . , S15, S16) to allow each one of said plurality of substations (S1, S2, S3, . . . , S15, S16) upon detection of its own substation identity to transfer a predetermined amount of upstream information packets in predetermined upstream timeslots to said main station (MS), characterized in that said time slot management method additionally includes embedding at least part of said substation identities (TEA12, TEA3, TEA7, . . . ) in a physical layer operation and maintenance part (PLOAM), said physical layer operation and maintenance part being a predefined part of one of said downstream information packets broadcasted from said main station (MS) to said plurality of substations (S1, S2, S3, . . . , S15, S16) to transport operation and maintenance information packets related to operation and maintenance functions.
A main station (MS) for inclusion in a time division multiple access network wherein said main station (MS) is to be coupled to each of a plurality of substations (S1, S2, S3, . . . , S15, S16) via the cascade connection of a common transmission link (Lc) and an individual user link (L1, L2, L3, . . . , L15, L16), said main station (MS) including a packet formatting module (PFM) to insert substation identities (TEA1, TEA12, TEA16, TEA3, TEA7, . . . ) in downstream information packets in order to broadcast said information packets from said main station (MS) to said plurality of substations (S1, S2, S3, . . . , S15, S16) to thereby allow each one of said plurality of substations (S1, S2, S3, . . . , S15, S16) upon detection of its own substation identity to transfer a predetermined amount of upstream information packets in predetermined upstream timeslots to said main station (MS), characterized in that said main station (MS) includes inserting means (INS) to insert at least part of said substation identities (TEA12, TEA3, TEA7, . . . ) in a physical layer operation and maintenance cell (PLOAM), said physical layer operation and maintenance cell (PLOAM) being a predefined part included in one of said downstream information packets broadcasted from said main station (MS) to said plurality of substations (S1, S2, S3, . . . , S15, S16) to transport operation and maintenance information packets related to operation and maintenance functions.
A substation (S3) for inclusion in a time division multiple access network, said time division multiple access network including a main station (MS) being coupled to each of a plurality of substations (S1, S2, S3, . . . , S15, S16) including said substation (S3) via the cascade connection of a common transmission link (Lc) and an individual user link (L1, L2, L3, . . . , L15, L16), substation identities (TEA1, TEA12, TEA16, TEA3, TEA7, . . . ) of said plurality of substations being broadcasted in downstream information packets from said main station (MS) to said substations (S1, . . . , S16) in order to allow each one of said plurality of substations (S1, S2, S3, . . . , S15, S16) upon detection of its own substation identity to transfer a predetermined amount of upstream information packets in predetermined upstream timeslots to said main station (MS), characterized in that said substation (S3) includes detecting means (DET) to detect in a physical layer operation and maintenance cell (PLOAM′) its own substation identity (TEA3) inserted by said main station (MS) in said physical layer operation and maintenance cell (PLOAM), said physical layer operation and maintenance cell (PLOAM) being a predefined part included in one of said downstream information packets broadcasted from said main station (MS) to said plurality of substations (S1, S2, S3, . . . , S15, S16) to transport operation and maintenance information packets related to operation and maintenance functions.
Dependencies are inferred from the claim text.
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Using time-division multiple access [TDMA]: for structure of frame, burst
Using optical switching: network aspects
Network aspects: provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network , ATM-based Passive Optical…
Network aspects: arbitration, scheduling or medium access control aspects
Term end not estimated
The present invention relates to a time slot management method for use in a time division multiple access network as described in the preamble of claim 1 and a main station and a substation realizing such a method as described in the preamble of claim 8 and claim 9, respectively.
Such a time slot management method, main station and substation are already known in the art, e.g. from the published European patent application with publication number 0 544 975 A1. Therein, a time slot management system is described which includes a time division multiple access system with a main station connected to a plurality of substations by means of a tree like network. Substation identities are broadcasted in downstream information packets from the main station to the substations in order to thereby allow each one of the substations upon detection of its own substation identity to transfer upstream information in upstream information packets in predefined upstream timeslots. This time slot management system allocates the time slots in a flexible and dynamically way. The needed bandwidth to transmit upstream information is requested by the substations to the main station and the substations are informed by the main station of the allocated timeslots.
A feature of the described time slot management system is that the downstream information packets are including a predetermined number of blocks each of which include a header part and an information part. In order to reduce the overhead of the downstream information packets a first step is realized to distribute the stream of substation identities over the header parts of this predetermined number of blocks and a second step is realized to performe only one error check for this predetermined number of blocks and to distribute the error check information bits over the header parts of the predetermined number of blocks. In this way, the overhead of one information packet is a reduced number of bits.
The above and other objects and features of the invention will become more apparent and the invention itself will be best understood by referring to the following description of an embodiment taken in conjunction with the accompanying drawings wherein:
FIG. 1 shows a block scheme of an embodiment of a time division multiple access network wherein the method of the invention is used;
FIG. 2 shows a downstream frame format and an upstream frame format used by the time division multiple access network of FIG. 1.
Referring to FIG. 1 a time slot management method used in a time division multiple access network will be described. First, the working of the time division multiple access network will be explained by means of a functional description of the blocks shown in FIG. 1. Based on this description, implementation of the functional blocks in FIG. 1 will be obvious to a person skilled in the art and will therefor not be described in detail. In addition, the principle working of the time slot management method following the invention will be described in further detail.
The time division multiple access network includes a main station MS and a plurality of substations S1, S2, S3, . . . , S15, S16. The main station MS is coupled to each substation S1, S2, S3, . . . , S15, S16 via the cascade connection of a common transmission link Lc and an individual user link L1, L2, L3, . . . , L15, L16.
The time division multiple access network is an optical network transporting asynchronous transfer mode ATM cells over optical fibers from the main station MS to the substations S1, S2, S3, . . . , S15, S16. The goal is to have a network which is transparent for ATM cells and which has an optimized throughput with minimal constraints on the optical components. Optical passive splitters which are not shown in the figure in order not to overload the figure are used in order to reach the substations S1, S2, S3, . . . , S15, S16.