# US 5,706,285 A · Network interfacing method and a network interface for a digital transmission network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,285 A - Document ID: US5706285A - Status: Granted - Kind: A - Application number: 08/318,787 - Filed: 1994-09-30 - Granted: 1998-01-06 - Earliest claimed: 1992-04-02 - Assignees: Nokia Telecommunications Oy - Inventors: Jaakko Saijonmaa; Seppo Pyhalammi - Web page: https://patentgrep.com/patent/US5706285A ## CPC - H04J 3/247: {ATM or packet multiplexing} - H04L 25/14: Channel dividing arrangements {, i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver} - H04Q 11/0478: {Provisions for broadband connections} - H04J 2203/0048: Network termination, e.g. NT1, NT2, PBX - H04J 2203/0089: Multiplexing, e.g. coding, scrambling, SONET - H04L 2012/5615: {Network termination, e.g. NT1, NT2, PBX} - H04L 2012/5646: {Cell characteristics, e.g. loss, delay, jitter, sequence integrity} - H04L 2012/5652: {Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly} - H04L 2012/5672: {Multiplexing, e.g. coding, scrambling} - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract A method for establishing a user-network interface in a digital transmission network for a cell-based digital 140 or 155 Mbit/s ATM signal, and a network interface embodying the method. The interface includes an input buffer controlled by a predetermined policing function for receiving the cell-based signal and adapting the transmission speed of the signal to the actual transmission speed of the transmission network; a mapper for forming cell blocks of N consecutive cells from the cell-based signal and for adding N overhead bytes to each cell block; and a multiplexer for multiplexing the output signal of the mapper byte by byte into N separate output signals of about 1.5 Mbit/s, 2 Mbit/s, 6 Mbit/s or 8 Mbit/s. ## Claims ### Claim 1 A method for establishing a user-network interface in a digital transmission network for a cell-based digital signal comprising cells of fixed length and having a high nominal bit rate, for an ATM signal, said method comprising the steps of: adapting the rate of the cell-based signal by a policing function to an actual transmission speed lower than said nominal bit rate; and mapping the rate-adapted cell-based signal into a group of lower-speed transmission signals for transmission over the transmission network, N being an integer which is greater than 2; said step of mapping comprising the steps of: a) forming cell blocks of N consecutive cells from the cell-based signal; b) adding N overhead bytes to each cell block to form a composite signal; c) multiplexing the composite signal to said N separate transmission signals. ### Claim 2 (depends on 1) The method according to claim 1, wherein said policing function utilizes the leaky bucket function. ### Claim 3 (depends on 1) The method according to claim 1, wherein each overhead byte comprises at least a cyclic counter value which is equal in all overhead bytes of one cell block and which is incremented by one N from one cell block to another. ### Claim 4 (depends on 1) The method according to claim 1, wherein the overhead bytes comprise a transmission signal number which is incremented from one overhead byte to another within the same cell block. ### Claim 5 (depends on 1) The method according to claim 1, wherein N synchronization words are added to the composite signal at intervals of M cell blocks. ### Claim 6 (depends on 1) Method according to claim 1, characterized in that the transmission signals received over the transmission network are demultiplexed at the reception end and restored to the cell-based signal, the rate of which is adapted to said high nominal bit rate. ### Claim 7 (depends on 2) The method according to claim 2, wherein each overhead byte comprises at least a cyclic counter value which is equal in all overhead bytes of one cell block and which is incremented by one or N from one cell block to another. ### Claim 8 (depends on 2) Method according to claim 2, wherein the overhead bytes comprise a transmission signal number which is incremented from one overhead byte to another within the same cell block. ### Claim 9 (depends on 1) The method according to claim 1, wherein N synchronization words are added to the composite signal at intervals of M cell blocks. ### Claim 10 (depends on 1) The method according to claim 1, further comprising: demultiplexing the transmission signals received over the transmission network at the reception end and restoring them to the cell-based signal, the rate of which is adapted to said high nominal bit rate. ### Claim 11 (depends on 1) The method of claim 1, wherein: said high nominal bit rate is 140 or 155 Mbits/s and said separate lower-speed transmission signals each have a bit rate of about 1.5, 2, 6 or 8 Mbits/s. ### Claim 12 (depends on 1) The method according to claim 1, wherein the multiplexing takes place byte by byte. ### Claim 13 A user-network interface in a digital transmission network for a cell-based digital signal comprising cells of fixed length and having a high nominal bit rate, the interface comprising: an input buffer means for receiving and buffering the cell-based signal; a policing means for controlling said buffer means to adapt the rate of the received cell-based signal to the actual transmission speed of the transmission network; a mapping means for forming cell blocks of N consecutive cells from the cell-based signal and for adding N overhead bytes to each cell block; a first multiplexing means for multiplexing the output signal of the mapping means byte by byte into N separate output signals of about 1.5 Mbit/s, 2 Mbit/s, 6 Mbit/s or 8 Mbit/s, N being an integer which is greater than 1. ### Claim 14 (depends on 13) The interface according to claim 13, wherein the network interface further comprises a first generator means for generating empty cells; a second generator means for generating control cells; a combiner means for combining cells from the first and the second generator means with the rate-adapted cell-based signal before applying the signal to the mapping means. ### Claim 15 (depends on 14) The interface according to claim 14, wherein the network interface further comprises a means for mapping at least one non-cell-based synchronous digital signal to the cells; a buffer means for adapting the rate of the obtained cell-based signal and for applying the rate-adapted signal to the combiner means for combining it with the output signal of the input buffer means. ### Claim 16 (depends on 13) The interface according to claim 13, further comprising a second multiplexing means for multiplexing the output signals of the first multiplexing means into the STM frames of a synchronous digital hierarchy. ### Claim 17 (depends on 13) The interface according to claim 13, further comprising a second multiplexing means for multiplexing the output signals of the first multiplexing means into the STM frames of a synchronous digital hierarchy. ### Claim 18 (depends on 14) The interface according to claim 14, further comprising a second multiplexing means for multiplexing the output signals of the first multiplexing means into STM frames of a synchronous digital hierarchy. ### Claim 19 (depends on 15) The interface according to claim 15, further comprising a second multiplexing means for multiplexing the output signals of the first multiplexing means into STM frames of a synchronous digital hierarchy. ### Claim 20 A method for establishing a user-network interface in a digital transmission network for a cell-based digital signal comprising cells of fixed length and having a high nominal bit rate, for an ATM signal, said method comprising the steps of: adapting the rate of the cell-based signal by a policing function to an actual transmission speed lower than said nominal bit rate; generating empty cells; generating control cells; combining said empty cells and said control cells with the rate-adapted cell-based signal, mapping the rate-adapted cell-based signal into a group of N separate lower-speed transmission signals for transmission over the transmission network, N being an integer higher than 1. ### Claim 21 (depends on 20) The method claim 20, wherein:said high nominal bit rate is 140 or 155 Mbits/s and said separate lower-speed transmission signals each have a bit rate of about 1.5, 2, 6 or 8 Mbits/s. ### Claim 22 A user-network interface in a digital transmission network for a cell-based digital signal comprising cells of fixed length and having a high nominal bit rate, said interface comprising: an input buffer means for receiving and buffering the cell-based signal; a policing means for controlling said buffer means to adapt the rate of the received cell-based signal to the actual transmission speed of the transmission network; a mapping means for forming cell blocks of N consecutive cells from the cell-based signal and for adding N overhead bytes to each cell block; a first multiplexing means for multiplexing the output signal of the mapping means byte by byte into N separate output signals of about 1.5 Mbit/s, 2 Mbit/s, 6 Mbit/s or 8 Mbit/s, N being integer higher than 1; a first generator means for generating empty cells; a second generator means for generating control cells; and a combiner means for combining cells from the first and the second generator means with the rate-adapted cell-based signal before applying the signal to the mapping means.