Method and apparatus for coordinating FDX and TDD communications in a communication system

Abstract

The present application discloses a method and a device for coordinating full-duplex FDX communication and time-division duplex TDD communication in a communication system. The method comprises: a first remote communication unit (121) performs a rf An upstream symbol having a first structure is transmitted to a first communication line, wherein a reception time t of a downstream symbol having the first structure is based on FDX‑DS‑RX and the first propagation delay t on the first communication line PD1 , reference time point t rf Determined as t rf =t FDX‑DS‑RX0 ‑t PD1 During the time interval assigned for upstream transmission on the second communication line, by the second remote communication unit (131) at t TDD_US_TX =t rf ‑t PD2 When t PD2 is a second propagation delay on the second communication line, so that the upstream symbol with the second structure transmitted by the second remote communication unit (131) is transmitted at the reference time point t rf The access node (110) is reached.

Description

[0001] This application is a divisional application of the invention patent application with application number 201880060368.3, application date September 10, 2018, and invention name “Method and device for coordinating FDX and TDD communications in a communication system”. Technical Field

[0002] The present invention relates to communication technology, and in particular to a method for coordinating communications in a communication system. Background Art

[0003] The discrete multi-tone (DMT) communications paradigm combined with full-duplex (FDX) transmission (all carriers are used simultaneously in both communication directions) has proven particularly successful in achieving record transmission rates over copper media such as unshielded twisted pair (UTP) or television broadcast coaxial cable.

[0004] FDX transmission can theoretically double the aggregate data rate compared to time division duplex (TDD) (such as used in G.fast), or frequency division duplex (FDD) (such as used in VDSL2).

[0005] In FDX, downstream (DS) and upstream (US) symbols are time aligned by the timing advance (TA) parameter. The purpose is to synchronize DS and US in such a way that both ends of the line start symbols at the same absolute time instance. In this way, the effect of propagation delay (PD) is balanced between DS and US, and cyclic extension (CE) can be minimized to be proportional to 1xPD + delay extension. Conceptually, CE is divided into a cyclic prefix (CP) to accommodate delay extension, and a cyclic suffix (CS) to accommodate propagation delay.

[0006] In TDD, such as in the G.fast standard, DS and US use different time slots. Full CE can only be used to mitigate delay spread (CE is proportional to delay spread). The impact of propagation delay only proves itself in the requirement on the gap size between US and DS subframes.

[0007] For the coexistence of FDX and TDD in the communication system, the range of G.fast line will be seriously affected because part of the cyclic extension of G.fast TDD line will be used to adapt the propagation delay in order to synchronize the NEXT (near end crosstalk) from the FDX line and the desired signal from the TDD line.

[0008] Therefore, an object of the present invention is to propose a synchronization scheme for the coexistence of FDX and TDD in a communication system without affecting the range of the G.fast line. Summary of the invention

[0009] The objects of the invention are achieved by the method and the device defined in the claims.

[0010] According to one aspect of the present invention, there is provided a method for coordinating communications in a communication system, the communication system comprising an access node, the access node being communicatively coupled to: a first set of remote communication units configured to operate in full-duplex FDX mode via corresponding multiple communication lines in the first set of communication lines, and a second set of remote communication units configured to operate in time division duplex TDD mode via corresponding multiple communication lines in the second set of communication lines; wherein a symbol transmitted on the first communication line has a first structure, on which a first remote communication unit belonging to the first set of remote communication units is connected to the access node, the first structure comprising a first cyclic prefix portion, a data portion, and a first cyclic suffix portion, and a cyclic extension including the first cyclic prefix portion and the first cyclic suffix portion has a predetermined duration; and a symbol transmitted on the second communication line has a second structure, on which a second remote communication unit belonging to the second set of remote communication units is connected to the access node, the second structure comprising a second cyclic prefix portion and a data portion, the second cyclic prefix portion having a predetermined duration, and the symbol having the first structure and the symbol having the second structure having the same symbol duration T symb The method comprises: the first remote communication unit at a reference time point t rf An upstream symbol having a first structure is transmitted to a first communication line, wherein a reception time t of a downstream symbol having the first structure is based on FDX-DS-RX and the first propagation delay t on the first communication line PD1 , reference time point t rf Determined as t rf =t FDX-DS-RX0 -t PD1 During the time interval assigned for upstream transmission on the second communication line, by the second remote communication unit at t TDD_US_TX =t rf -t PD2 When t PD2 is the second propagation delay on the second communication line.

[0011] In a preferred embodiment, the method further comprises: determining a first propagation delay t PD1 and the second propagation delay t PD2 ; Sending a first propagation delay t to the first remote communication unit PD1 .

[0012] In a preferred embodiment, the FDX frame includes a first FDX subframe and a second FDX subframe, the first FDX subframe includes a first number of symbols with a first structure, and the second FDX subframe includes a second number of symbols with the first structure; the TDD frame includes a downstream subframe and an upstream subframe, the downstream subframe includes a first number of symbols with a second structure, and the upstream subframe includes a second number of symbols with the second structure; wherein the upstream subframe is transmitted with a delay equal to the second propagation delay t PD2 The amount of time that is transmitted before the second FDX subframe is transmitted.

[0013] In a preferred embodiment, the first FDX subframe is a downstream priority subframe, where priority is given to downstream communications from the access node to the first set of remote communication units, and the second FDX subframe is an upstream priority subframe, where priority is given to upstream communications from the first set of remote communication units to the access node.

[0014] In a preferred embodiment, the method further comprises: determining the time interval t applied at the access node g2_TDD is a predetermined length, the time interval t g2_TDD separating the end of a downlink subframe transmitted to the second communication link from the beginning of a subsequent uplink subframe received from the second communication link; determining a time gap t applied at the first remote communication unit and the access node g1’_FDX t g1’_FDX =t g2_TDD -t PD1 , the time interval t g1’_FDX separating the end of a first FDX subframe received from the first communication line from the beginning of a second FDX subframe transmitted onto the first communication line; determining a time gap t applied at the second remote communication unit g1’_TDD t g1’_TDD =t g2_TDD -2t PD2 , the time interval t g1’_TDD Separating the end of a downlink subframe received on the second communication link from the beginning of a subsequent uplink subframe transmitted on the second communication link; applying a time interval t at the first remote communication unit and the access node g1’_FDX , and applying a time interval t at the second remote communication unit g1’_TDD .

[0015] In a preferred embodiment, according to the symbol duration T symb and the time interval t applied at the access node g1_TDD， The predetermined length is determined as t g2_TDD =T symb -t g1_TDD, which time gap separates the end of an upstream frame received from the second communication line from the beginning of a subsequent downstream subframe transmitted onto the second communication line.

[0016] In a preferred embodiment, the first communication line and the second communication line are in the same binder.

[0017] In a preferred embodiment, the predetermined duration is determined to accommodate the delay spread and propagation delay of the communication line having the longest supported cycle length.

[0018] In a preferred embodiment, the method further comprises: at a reference time point t rf , controlling the access node to transmit symbols having a first structure to at least one telecommunication unit belonging to a first set of telecommunication units.

[0019] According to another aspect of the present invention, a communication controller for coordinating communications in a communication system is provided, the communication system comprising an access node, the access node being communicatively coupled to: a first set of remote communication units configured to operate in full-duplex FDX mode via corresponding multiple communication lines in the first set of communication lines, and a second set of remote communication units configured to operate in time-division duplex TDD mode via corresponding multiple communication lines in the second set of communication lines; wherein a symbol transmitted on the first communication line has a first structure on which a first remote communication unit belonging to the first set of remote communication units is connected to the access node, the first structure comprising a first cyclic prefix portion, a data portion, and a first cyclic suffix portion, and a cyclic extension including the first cyclic prefix portion and the first cyclic suffix portion has a predetermined duration; and a symbol transmitted on the second communication line has a second structure on which a second remote communication unit belonging to the second set of remote communication units is connected to the access node, the second structure comprising a second cyclic prefix portion and a data portion, the second cyclic prefix portion having a predetermined duration, and the symbol having the first structure and the symbol having the second structure having the same symbol duration T symb The communication controller is configured to: control the first remote communication unit at a reference time point t rf The upstream symbol with the first structure is transmitted to the first communication line, wherein the reception time t of the downstream symbol with the first structure is based on FDX-DS-RX and a first propagation delay t on the first communication line PD1 , reference time point t rf Determined as t rf =t FDX-DS-RX0 -t PD1 During the time interval specified for uplink transmission on the second communication line, control the second remote communication unit at tTDD_US_TX =t rf -t PD2 When t PD2 is the second propagation delay on the second communication line.

[0020] According to another aspect of the present invention, there is provided an access node comprising a communication controller according to the present invention.

[0021] According to another aspect of the present invention, there is provided a communication system comprising an access node, the access node being communicatively coupled to: a first set of remote communication units configured to operate in full-duplex FDX mode via corresponding multiple communication lines of the first set of communication lines, and a second set of remote communication units configured to operate in time division duplex TDD mode via corresponding multiple communication lines of the second set of communication lines; wherein a symbol transmitted on the first communication line has a first structure, on which a first remote communication unit belonging to the first set of remote communication units is connected to the access node, the symbol comprises a first cyclic prefix portion, a data portion and a first cyclic suffix portion, and a cyclic extension including the first cyclic prefix portion and the first cyclic suffix portion has a predetermined duration; and a symbol transmitted on the second communication line has a second structure, on which a second remote communication unit belonging to the second set of remote communication units is connected to the access node, the symbol comprises a second cyclic prefix portion and a data portion, the second cyclic prefix portion has a predetermined duration, and the symbol having the first structure and the symbol having the second structure have the same symbol duration T symb ; wherein communications in the communication system are coordinated according to the present invention.

[0022] According to another aspect of the invention, a customer premises equipment CPE is provided, characterized in that the communication of the CPE is coordinated according to the invention.

[0023] The solution in the present invention makes it possible to have coexistence of FDX and TDD in a communication system without affecting the range of the TDD line. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] A more complete understanding of the features and advantages of the present invention will be obtained by reading the following detailed description of the preferred embodiments with reference to the accompanying drawings.

[0025] Figure 1 A schematic topology of a communication system according to an embodiment of the present invention is depicted.

[0026] Figure 2 A schematic timing diagram of an embodiment of the present invention is depicted.

[0027] Figure 3A schematic timing diagram of another embodiment of the present invention is depicted.

[0028] The same or similar reference numerals refer to the same or similar parts or components. DETAILED DESCRIPTION

[0029] Exemplary embodiments of the present application are shown in detail herein and are illustrated in the accompanying drawings by way of example. It should be understood that, although specific exemplary embodiments are discussed herein, it is not intended to limit the scope of the present invention to such embodiments. On the contrary, it should be understood that the exemplary embodiments discussed herein are for illustrative purposes, and without departing from the scope of the present invention as defined in the claims, modifications and alternative embodiments may be implemented. Similarly, for the purpose of describing exemplary embodiments, the specific structural and functional details disclosed herein are only representative. However, the invention described herein may be embodied in many alternative forms and should not be construed as being limited to the embodiments set forth herein.

[0030] Figure 1 A schematic topology of a communication system according to an embodiment of the present invention is shown.

[0031] like Figure 1 As shown in , the communication system 100 comprises an access node 110, a first set 121, 122 of remote communication units and a second set 131, 132 of remote communication units.

[0032] Specifically, the access node 110 can be implemented as a distribution point unit operating according to G.fast legacy TDD and a new FDX communication technology to be deployed to coexist with the legacy TDD G.fast communication technology. The access node 110 is usually deployed in a remote location closer to the subscriber's house, in a street cabinet, on a utility pole, in the basement of a building, etc.

[0033] The first set 121, 122 of remote communication units are configured to operate in FDX mode.The second set 131, 132 of remote communication units are configured to operate in TDD mode.

[0034] In one embodiment, the access node 110 includes a first set 111, 113 of communication units operating in FDX mode, which are connected to a first set 121, 122 of remote communication units through a respective plurality of communication lines in the first set of communication lines. The access node 110 also includes a second set 112, 114 of communication units operating in TDD mode, which are connected to a second set 131, 132 of remote communication units through respective communication lines in the second set of communication lines. The communication lines are typically copper unshielded twisted pairs (UTP).

[0035] In one embodiment, access node 110 also includes a communication controller 115 for coordinating communications in communication system 100 .

[0036] Specifically, in the following, embodiments of the present invention will be described with respect to a first communication line and a second communication line. The first communication line connects two communication units operating in FDX mode, namely, a first remote communication unit 121 and a first communication unit 111 in the access node 110. The second communication line connects two communication units operating in TDD mode, namely, a second remote communication unit 131 and a second communication unit 112 in the access node 110. Advantageously, the first communication line and the second communication line are in the same wrapper.

[0037] Specifically, the communication units 111 and 112 at the access node, the first remote communication unit 121, and the second remote communication unit 131 include a transmitter (TX) and a receiver (RX), respectively. The first remote communication unit 121 and the second remote communication unit 131 can be implemented in a customer premises equipment (CPE). For example, the CPE can be implemented as a G.fast gateway, a router, a bridge, or a network interface card (NIC).

[0038] Figure 2 A schematic timing diagram of an embodiment of the present invention is shown.

[0039] like Figure 2 As shown in , the symbols transmitted in two directions, i.e., the upstream direction (from the first remote communication unit 121 to the access node 110) and the downstream direction (from the access node 110 to the first remote communication unit 121) on the first communication line have a first structure. The symbol having the first structure includes a first cyclic prefix part CP1, a data part and a first cyclic suffix part CS1, and the cyclic extension CE including the first cyclic prefix part CP1 and the first cyclic suffix part CS1 has a predetermined duration t CE .

[0040] The symbols transmitted in both directions, i.e., the upstream direction (from the second remote communication unit 131 to the access node 110) and the downstream direction (from the access node 110 to the second remote communication unit 131) on the second communication line have a second structure. The symbols having the second structure include a second cyclic prefix part CP2 and a data part, the second cyclic prefix part CP2 having a predetermined duration t CE .

[0041] The symbols having the second structure may further include a small cyclic suffix portion (not shown) for windowing purposes.

[0042] Furthermore, the symbol having the first structure and the symbol having the second structure have the same symbol duration T symb Therefore, the duration of the data portion in the symbol having the first structure is equal to the duration of the data portion in the symbol having the second structure.

[0043] In a preferred embodiment, the predetermined duration t CE is determined to accommodate the delay spread and propagation delay of the communication line with the longest supported loop length. For symbols having the first structure, the duration of the cyclic prefix part CP1 is determined to accommodate the delay spread, and the duration of the cyclic suffix part CS1 is determined to accommodate the propagation delay.

[0044] According to an embodiment of the present invention, the communication controller 115 is configured to control the first remote communication unit 121 and the access node 110 to transmit symbols having a first structure to the first communication line at the same absolute time so as to balance the impact of the propagation delay between the DS and the US and maximize the supported loop length.

[0045] Specifically, the communication controller 115 is configured to control the access node 110 to rf , that is, t FDX_DS_TX =t rf When the downstream symbol (FDX_DS) having the first structure is transmitted to the first remote communication unit 121. Figure 2 In the embodiment shown, t rf =0.

[0046] Accordingly, the FDX_DS symbol transmitted by the access node 110 is transmitted at t FDX_DS_RX =t rf +t PD1 arrives at the first remote communication unit 121 at t PD1 is the first propagation delay on the first communication line.

[0047] In one embodiment, the first remote communication unit 121 receives the FDX_DS symbol based on the reception time t FDX_DS_RX and the first propagation delay t PD1 , to synchronize with the access node 110. Therefore, the reference time t of the first remote communication unit 121 can be rf Determined as t rf =t FDX_DS_RX -t PD1 .

[0048] In one embodiment, the first propagation delay is determined by the access node 110 and transmitted to the first remote communication unit 121. Alternatively, the first propagation delay may be determined by the first remote communication unit 121 directly.

[0049] The first remote communication unit 121 determines a reference time t rf Afterwards, the first remote communication unit 121 at the reference time point t rf The upstream symbol (FDX_US) having the first structure is transmitted to the first communication line. The FDX_US symbol transmitted by the first remote communication unit 121 is transmitted at t FDX_US_RX =t rf +t PD1 When the access node 110 is reached.

[0050] Furthermore, the communication controller 115 is configured to control the second remote communication unit 131 to transmit the signal at t TDD_US_TX =t rf -t PD2 When t PD2 is the second propagation delay on the second communication line. Therefore, the TDD_US symbol transmitted by the second remote communication unit 131 at the reference time point t rf Access node 110 is reached.

[0051] At the access node 110, the RX FFT window has a predetermined duration that is equal to the duration of the data portion of a symbol. Figure 2 As shown, the RX FFT window starts at the time point where the data portion of the TDD_US symbol begins. PD1 ≤t CS1 And since the cyclic suffix part CS1 also contains the cyclic extension of the data part, it is possible to find such an RX FFT window that does not include any symbol transition for the directly received symbols and for the symbols received through interference (ECHO, NEXT, FEXT), while being away from the cyclic prefix part CP1 and the corresponding inter-symbol interference (ISI). In this way, the mutual orthogonality between the carriers is guaranteed. In general, as Figure 2 As shown in , the RX FFT window is selected to be as far away from the cyclic prefix part CP1 as possible.

[0052] According to the present invention, it is possible to combine an FDX symbol structure comprising a first cyclic prefix part and a first cyclic suffix part, which are necessary for implementing FDX for FDX line operation, with a maximum cyclic prefix part of a TDD symbol, which results in the maximum possible reach of the TDD line for a given cyclic extension length.

[0053] exist Figure 2In the present invention, the present invention is described in detail with respect to symbols. In operation, a plurality of symbols are transmitted continuously in a subframe. In the following, the present invention will be described with respect to subframes.

[0054] Figure 3 A schematic timing diagram of another embodiment of the present invention is shown.

[0055] like Figure 3 As shown in , the TDD frame transmitted on the second line includes a downstream subframe, an upstream subframe and a necessary guard time therebetween.

[0056] The communication controller 115 is configured to determine the time interval t applied at the access node 110 g2_TDD The time interval is a predetermined length that separates the end of a downstream subframe transmitted onto the second communication line from the beginning of a subsequent upstream subframe received from the second communication line.

[0057] In one embodiment, the predetermined length is based on the symbol duration T symb and the time interval t applied at the access node 110 g1_TDD The time interval is determined to separate the end of an upstream frame received from the second communication link from the start of a subsequent downstream frame transmitted on the second communication link. g2_TDD =T symb -t g1_TDD .

[0058] exist Figure 3 In the downlink subframe, M ds downstream symbols having a second structure, and the uplink subframe includes M us upstream symbols with the second structure. Therefore, the duration of the TDD frame is T F_TDD It can be expressed as T F_TDD =(M ds +M us +1)×T symb .

[0059] Then, according to Figure 3 , the time interval t applied at the second remote communication unit 131 g1’_TDD can be determined as t g1’_TDD =t g2_TDD -2t PD2 , which separates the end of the downstream subframe received from the second communication line from the beginning of the subsequent upstream subframe transmitted on the second communication line. In one embodiment, the time interval t g1’_TDD The data may be transmitted to the second remote communication unit 131 so that it may be applied to the second remote communication unit 131 .

[0060] exist Figure 3 In the illustrated embodiment, FDX and conventional TDD coexist in the communication system, and the FDX frame is set to have the same length T as the conventional TDD frame. F_FDX =T F_TDD =(M ds +M us +1)×T symb . Specifically, Figure 3 The FDX frame in the embodiment includes a first FDX subframe and a second FDX subframe and a necessary guard time therebetween. The first FDX subframe includes M ds symbols having a first structure, and the second FDX subframe includes M us Thus, the first FDX subframe has the same duration as a downstream subframe in the second lane, and the second FDX subframe has the same duration as an upstream subframe in the second lane.

[0061] Specifically, in one embodiment, the first FDX subframe and the second FDX subframe may correspond to FDX transmissions that are not prioritized.

[0062] In another embodiment, the first FDX subframe is a downstream priority subframe, wherein priority is given to downlink communications from the access node 110 to the first set 121, 122 of remote communication units, and the second FDX subframe is an upstream priority subframe, wherein priority is given to uplink communications from the first set 121, 122 of remote communication units to the access node 110, for example, as described in EP application No 16306744.0 entitled “Method And Apparatus For Full-Duplex Communication over Wired Transmission Media” filed by Alcatel-Lucent on December 20, 2016.

[0063] exist Figure 3 , the vertical dashed line represents the absolute time aligned across the access node 110 , the first telecommunication unit 121 , and the second telecommunication unit 131 .

[0064] The vertical dashed lines on the left indicate the start times of TDD and FDX frames. Figure 1 It can be seen that the TDD frame and the FDX frame start at the same time.During the duration of the downstream subframe, the symbols transmitted on the first communication line and the second communication line are aligned with respect to their transmission time.

[0065] The middle vertical dashed line aligns the reception time of the upstream subframe with the transmission time of the second FDX subframe. Figure 3It can be seen that the time before the second FDX subframe that the upstream subframe is transmitted is equal to the second propagation delay t PD2 Therefore, while the second FDX subframe is being transmitted, the upstream subframe is being received.

[0066] The vertical dashed lines on the right indicate the start times of subsequent TDD and FDX frames.

[0067] To ensure that the second FDX subframe is transmitted while the upstream subframe is being received, the communication controller 115 is further configured to determine the time interval t applied at the first remote communication unit 121 and the access node 110. g1'_FDX t g1′_FDX =t g2_TDD -t PD1 , which time interval separates the end of a first FDX subframe received from the first communication line and the beginning of a subsequent second FDX subframe transmitted onto the first communication line.

[0068] The communication controller 115 is further configured to apply a time interval t g1'_FDX In one embodiment, the time interval t g1'_TDD is transmitted to the second remote communication unit 131 so that it can be applied to the second remote communication unit 131 .

Claims

1. A method of coordinating communications in a communication system, the communication system comprising an access node, the access node being communicatively coupled to: a first set of remote communication units configured to operate in full duplex FDX mode via a respective plurality of the first set of communication lines, and a second set of remote communication units configured to operate in a time division duplex (TDD) mode via a respective plurality of the second set of communication lines; wherein symbols transmitted on a first communication line, which connects a first remote communication unit belonging to the first set of remote communication units to the access node, have a first structure, and symbols transmitted on a second communication line, which connects a second remote communication unit belonging to the second set of remote communication units to the access node, have a second structure, and the symbols having the first structure and the symbols having the second structure have the same symbol duration T symb ; The method of coordination includes controlling upstream symbols having the second structure to be received by the access node from the second communication line at the same time as downstream symbols having the first structure are sent by the access node to the first communication line.

2. The method according to claim 1, wherein: - an FDX frame comprises a first FDX subframe and a second FDX subframe, wherein the first FDX subframe comprises a first number of symbols having the first structure, and the second FDX subframe comprises a second number of symbols having the first structure; - A TDD frame comprises a downstream subframe and an upstream subframe, the downstream subframe comprising the first number of symbols having the second structure, the upstream subframe comprising the second number of symbols having the second structure.

3. The method according to claim 2, further comprising: - determining a second propagation delay t on the second communication line PD2 , - controlling the transmission of an upstream TDD subframe by the second remote communication unit and the transmission of a second FDX subframe by the access node so that the upstream TDD subframe is transmitted with a delay equal to the second propagation delay t PD2 The amount of time that precedes the transmission of the second FDX subframe is sent.

4. The method according to claim 2, further comprising: Determine a first time interval t to be applied at the first remote communication unit g1’_FDX , the first time gap separates the end of a first FDX subframe received at the first remote communication unit from the beginning of a subsequent second FDX upstream subframe sent by the first remote communication unit onto the first communication line.

5. The method according to claim 4, further comprising: - determining a first propagation delay t on said first communication line PD1 ; - determining a second time gap t to be applied at said access node g2_TDD , the second time gap separates the end of a downstream subframe sent on the second communication line from the beginning of a subsequent upstream subframe received from the second communication line; - Determine the first time interval t g1’_FDX t g1’_FDX =t g2_TDD -t PD1 .

6. The method of claim 2 , wherein the first FDX subframe is a downstream priority subframe, wherein priority is given to downstream communications from an access node to the first set of remote communication units, and the second FDX subframe is an upstream priority subframe, wherein priority is given to upstream communications from the first set of remote communication units to the access node.

7. The method according to claim 5, further comprising: - determining a third time interval t to be applied at said second remote communication unit g1’_TDD The third time gap is used to separate the end of the downstream subframe received from the second communication line from the beginning of the subsequent upstream subframe sent to the second communication line by t g1’_TDD =t g2_TDD -2t PD2 .

8. The method according to claim 2, wherein the method comprises: Determine a fourth time gap t to be applied at the access node g1_TDD , the fourth time gap separates the end of the upstream subframe received from the second communication line from the beginning of a subsequent downstream subframe sent on the second communication line.

9. The method according to claim 8, wherein the second time interval t g2_TDD Determined as t g2_TDD =T symb -t g1_TDD , the second time interval t g2_TDD An end of a downstream subframe sent onto the second communication line is separated from a beginning of a subsequent upstream subframe received from the second communication line at the access node.

10. The method of claim 1, wherein the first communication line and the second communication line are in the same binding.

11. The method according to claim 1, further comprising: - controlling the first telecommunication unit and the second telecommunication unit so that: - the first remote communication unit will be at the reference time t rf The upstream symbol with the first structure is sent to the first communication line, wherein the reception time t of the downstream symbol with the first structure is based on FDX_DS_RX and a first propagation delay t on the first communication line PD1 , the reference time point t rf Determined as t rf =t FDX_DS_RX -t PD1 ; - the second remote communication unit will, during the time interval assigned for upstream transmission on the second communication line, TDD_US_TX =t rf -t PD2 When t PD2 is a second propagation delay on the second communication line.

12. The method according to claim 11, further comprising: Control the access node at the reference time point t rf , sending symbols having the first structure to at least one remote communication unit belonging to the first set of remote communication units.

13. A communication controller for coordinating communications in a communication system, the communication system comprising an access node, the access node being communicatively coupled to: a first set of remote communication units configured to operate in full duplex FDX mode via a respective plurality of the first set of communication lines, and a second set of remote communication units configured to operate in a time division duplex (TDD) mode via a respective plurality of the second set of communication lines; wherein symbols transmitted on a first communication line, which connects a first remote communication unit belonging to the first set of remote communication units to the access node, have a first structure, and symbols transmitted on a second communication line, which connects a second remote communication unit belonging to the second set of remote communication units to the access node, have a second structure, and the symbols having the first structure and the symbols having the second structure have the same symbol duration T symb ; The communication controller is configured to control upstream symbols having the second structure to be received by the access node from the second communication line simultaneously with downstream symbols having the first structure being sent by the access node to the first communication line.

14. The communications controller of claim 13, wherein the communications controller is included in an access node.

15. A customer premises equipment device, comprising: at least one processor; and at least one memory including computer program code; The at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least perform: - operating in a full duplex FDX mode when receiving and / or transmitting signals over a first set of communication lines, or operating in a time division duplex TDD mode when receiving or transmitting signals from a second set of communication lines, the symbols of the FDX mode having a first structure and the symbols of the TDD mode having a second structure, - receiving instructions from a communications controller for controlling the operation of the device so that: - When operating in full-duplex FDX mode, at reference time t rf sending upstream symbols having said first structure, when operating in time division duplex, TDD, mode, during a time interval assigned for upstream transmission on a communication line of said second set of communication lines, at t TDD_US_TX =t rf -t PD2 When sending the upstream symbol with the second structure, t PD2 is a second propagation delay in the TDD mode and is received from the communication controller.

16. An access node, comprising: at least one processor; and at least one memory including computer program code; The at least one memory and the computer program code are configured to, with the at least one processor, cause the access node to at least perform: - operating in a full duplex FDX mode when receiving and / or transmitting signals through a first set of communication lines, and operating in a time division duplex TDD mode when receiving or transmitting signals from a second set of communication lines, wherein symbols transmitted on a first communication line in the first set of communication lines have a first structure, and symbols transmitted on a second communication line in the second set of communication lines have a second structure, and symbols having the first structure and symbols having the second structure have the same symbol duration T symb ; - receiving upstream symbols having the second structure through the communication lines in the second set while sending downstream symbols having the first structure through the communication lines in the first set.

17. The access node of claim 16, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the access node to at least further execute: - determining a first propagation delay t on said communication lines in said first set PD1 , - determining a second propagation delay t on said communication lines in said second set PD2 , - Determine the second time interval t g2_TDD , the second time gap is used to separate the end of a downstream subframe sent on the communication line in the second set from the beginning of a subsequent upstream subframe received from the communication line in the second set, Whereby an FDX frame comprises a first FDX subframe and a second FDX subframe, wherein the first FDX subframe comprises a first number of symbols having the first structure and the second FDX subframe comprises a second number of symbols having the first structure; and whereby The TDD frame includes a downstream subframe and an upstream subframe, the downstream subframe includes the first number of symbols having the second structure, and the upstream subframe includes the second number of symbols having the second structure.

18. The access node of claim 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the access node to at least further execute: Determine the fourth time interval t g1_TDD , the fourth time gap is used to separate the end of the upstream subframe received from the second communication line from the beginning of a subsequent downstream subframe sent to the second communication line.

Images