WO2011035796A1

WO2011035796A1 - Method for transmitting/receiving payload data with a high data rate, transmitter, receiver and adaption layer

Info

Publication number: WO2011035796A1
Application number: PCT/EP2009/006909
Authority: WO
Inventors: Peter Jung; Guido Bruck; Andreas Waadt; Alexander Viessmann; Friedbert Berens
Original assignee: Universität Duisburg-Essen; FBConsulting S.à.r.l.
Priority date: 2009-09-24
Filing date: 2009-09-24
Publication date: 2011-03-31
Also published as: EP2481247A1

Abstract

A method as well as a transmitter, a receiver and an adaption layer allowing transmission and/or reception of payload data with a high data rate is described. A high data rate platform (502, 504) and a low data rate platform (506, 508) are provided. The payload data is transmitted and/or received via the high data rate platform (502, 504), while the signaling data associated with the payload data is transmitted and/or received via the low data rate platform (506, 508).

Description

Method for Transmitting Receiving Payload Data with a High Data Rate,

Transmitter, Receiver and Adaption Layer

Description

The present invention relates to the field of high data rate information transmission in wireless communication systems and, more specifically, to a method for transmitting or receiving payload data with a high data rate, a transmitter, a receiver and an adaption layer. More specifically, embodiments of the invention relate to ultra wide band (UWB) transmitter, receiver or transceiver platforms allowing a high data rate transmission.

In the art, HDR (HDR = High Data Rate) ultra wideband systems are known. The operation principles of such systems offer a wide range of applications. Fig. 1 depicts an exam- pie of an HDR TRX (TRX = Transmitter/Receiver) architecture. In Fig. 1 , a first high data rate transceiver HDR-TRXi 100 is shown that comprises an HDR-MAC layer 102 and an HDR-PHY layer 104 that are coupled to an antenna ANTi for a wireless communication with a remote high data rate transceiver 200, also comprising an antenna ANT₂ and having the same structure as the first transceiver 100. The physical layer utilizes the unlicensed 3100-10600 MHz frequency band to transmit and receive UWB signals, supporting data rates of 53,3 Mb/s, 80 Mb/s, 106,7 Mb/s, 160 Mb/s, 200 Mb/s, 320 Mb/s, 400 Mb/s, and 480 Mb/s. The UWB spectrum is divided into 14 bands; each with a bandwidth of 528 MHz .The HDR-UWB utilizes a Multi-Band Orthogonal Frequency Division Modulation (MBOFDM) scheme to transmit information. A total of 110 sub-carriers (100 data carriers and 10 guard carriers) are used per band to transmit the information. In addition, 12 pilot subcarriers allow for coherent detection. Frequency-domain spreading, time-domain spreading, and forward error correction (FEC) coding are used to vary the data rates. The FEC used is a convolution code with coding rates of 1/3, 1/2, 5/8 and ¾. Coded data is then spread using a time-frequency code (TFC).

A PHY packet (PHY = Physical Layer) contains a PLCP preamble (PLCP = Physical Layer Convergence Protocol), a PLCP Header (the PHY header, the MAC header (MAC = Medium Access Control) and its channel encoding components), and a PSDU (PSDU = PHY Service Data Unit), i.e. the payload plus its channel encoding and pad bits (see e.g. ECMA, "Standard ECMA-368: High Rate Ultra Wideband PHY and MAC Standard," Dec. 2008org/publications/standards/Ecma). The HDR-MAC layer provides medium resource control so that upper layers can efficiently and effectively communicate with their counterparts in other devices. It makes sure that the users of the medium do not interfere with each other even if they are using different applications. It also allows dynamic control of the communications parameters in order to address the varying wireless channel conditioning that can cause data packet corruption or loss (see e.g. Ghobad Heidari, WiMedia UWB for W-USB and Bluetooth Interpretation of standards, regulations and applications, Wiley & Sons, 2008).

The general frame format of the MAC sub-layer is shown in Fig. 2. The MAC frame con- tains the PHY header, the MAC header, the payload, and the FCS (FCS = Frame Check Sequence).

The PHY header comprises the basic parameters of the PHY protocol, e.g. the rate, the length, the scrambler, burst mode, preamble type, TFC (TFC = Time-Frequency Code), and band group fields.

The MAC header contains frame control information which address the type of frame being received, the AC policy (AC = Acknowledgement), the destination and source IDs, and the number of the frame, etc. The payload may hold a range from 0 to 4095 bytes of user information for non-secure and up to 4075 bytes of user information for a secure pay- load .

There are six frame types defined in the MAC sublayer specification: Beacon, Control, Command, Data, and Aggregated. Besides these, there are three reserved for further expan- sion of the standard. Fig. 2 depicts the general format of these frame types.

For Beacon, Control, and Command frames, the payloads are used for carrying signaling information. Although the Command and Control frames are available for transmission in any MAS (MAS = Medium Access Slot) during a superframe, most signal- ing/command/control information will be exchanged within the Beacon frames during the BP (BP = Beacon Period; see e.g. Ghobad Heidari, WiMedia UWB for W-USB and Bluetooth Interpretation of standards, regulations and applications, Wiley & Sons, 2008).

The HDR-MAC Data frames are used for the exchange of the MAC client data among de- vices. The data may be sent in unicast, multicast, or broadcast fashion.

The Aggregated data frames are provided in the MAC to allow for a more efficient delivery of short MSDUs (MSDU = MAC Service Data Unit). When possible, the MAC may aggregate several MSDUs into an Aggregated data frame to create the MPDU (MPDU = MAC Protocol Data Unit). In accordance with the ECMA standard, the maximum size of an Aggregated data frame is still 4095 bytes. In the HDR-MAC signaling frames, e.g. the Beacon, Control, or Command frames, the payloads are used for signaling information, i.e. the payload is not user data but control data. Although the Command and Control frames are available for transmission in any MAS during a superframe, most signaling/command/control information will be exchanged within Beacon frames during the BP.

The Beacon frames are transmitted during the BP only. From a PHY perspective, the Beacon packet always contains a standard preamble and is sent at the lowest data rate (e.g. 53.3 Mbps) to ensure the highest transmission reliability. Each Beacon packet is supposed to be transmitted at the beginning of a Beacon slot and may extend beyond the duration of that slot. The Beacon frame's payload comprises MAC-level control information which is broadcast to the neighbors.

The Control frames are essentially used for the purpose of controlling traffic flow during regular MASs (the MASs that will not overlap the BP). The Control frames comprise spe- cial frame subtypes, control acknowledgments, PCA initiation or termination (PCA = Prioritized Contention Access), as well as any application-specific controls. The Command frames are used for sending commands or requests from one device to another.

Now the power consumption in an HDR-UWB system will be discussed. In an HDR-UWB system high power consumption often imposes a limitation on the use of UWB for applications where low power is desired, or sometimes even required. Although the MAC and higher layers significantly affect the overall power consumption of the system, they generally have little impact on the design of the hardware system. The physical layer specification, however, is directly related to the operation of the hardware and needs to be fully comprehended in order to achieve a hardware design with optimal power consumption (see e.g. Anantha P. Chandrakasan et.al, "Low-Power Impulse UWB Architectures and Circuits", in Proceedings of the IEEE Vol. 97, No. 2,pp. 332-352, February 2009). Fig. 3 shows the average transmit power as a function of the data rates for a standard multiband scheme.

Table 1 illustrates the power consumption numbers for another example, a multiband OFDM system. Table 1 illustrates the transmit power in an OFDM UWB system using a 90nm signal processing chip and a 130 run signal processing chip for a transmission with 110, 200, and 480 Mb/s (see e.g. Multiband OFDM Physical Layer Specification (Revl), Jan 14,2005. WiMedia Alliance; ht†p://vNdrnedia.org/en/resources/mboa_archives.asp).

Table 1

Thus, for an HDR system operating in accordance with the above described principles, a stable high data throughput is an essential demand to support applications like multimedia and web services. However, this advantage is obtained in exchange for higher power con- sumption. Such high power consumption is disadvantages in many applications, especially in mobile or wireless applications using batteries or the like as a power supply. This may result in a degradation of the performance.

It is an object of the invention to provide for an approach allowing for the transmission of data at a high data rate that avoids or reduces performance degradation.

This object is achieved by a method of claim 1, a transmitter of claim 11, a receiver of claim 18 and an adaption layer of claim 21.

The present invention provides a method for transmitting or receiving payload data with a high data rate in a system comprising a high data rate platform and a low data rate platform, the method comprising: transmitting or receiving the payload data via the high data rate platform; and transmitting or receiving the signaling data associated with the payload data via the low data rate platform. The present invention further provides a transmitter for transmitting payload data with a high data rate, the transmitter comprising: a high data rate platform; a low data rate platform; and a controller configured to transmit the payload via the high data rate platform, and to transmit the signaling data associated with the payload data via the low data rate platform. Further, the present invention provides a receiver for receiving payload data with a high data rate, the receiver comprising: a high data rate platform; a low data rate platform; and a controller configured to receive the payload data via the high data rate platform, and to receive the signaling data associated with the payload data via the low data rate platform.

In addition, the present invention provides an adaption layer for routing a data stream between a MAC layer of a high data rate platform and a PHY layer of the high data rate platform or between the MAC layer of the high data rate platform and an MAC layer of a low data rate platform, the adaption layer being configured to analyze a data stream to be transmitted in accordance with a high data rate protocol, route a payload data frame in the data stream to the PHY layer of the high data rate platform for transmission, and to route a signaling frame in the data stream to the MAC layer of the low data rate platform for transmission.

In an embodiment, the adaption layer is further configured to receive from the PHY layer of the high data rate platform a payload frame, to receive from the MAC layer of the low data rate platform a signaling frame, and to combine the received payload frame and the received signaling frame to a data stream in accordance with the high data rate protocol. Embodiments of the invention provide a combined HDR/LDR system (LDR= Low Data Rate) that overcomes or reduces any degradations in performance and supports a wider range of applications. For example, the power consumption in an HDR system which is modulation-dependent may be reduced in accordance with the embodiments of the inven- tion as in a LDR system the power consumption is throughput dependent. To take advantage of LDR power consumption in a combined the HDR/LDR system, the traffic may be split into data and signaling traffic. According to an embodiment, the data traffic is transmitted via the HDR-PHY layer and the signaling traffic is transmitted over the LDR system.

To be more specific, in the HDR system the power consumption is high and generally related to the OFDM modulation scheme, but does not really change with the throughput. However, the high throughput in the HDR system comes from the data frames size and is not affected by the signaling frames. Thus, the power used for sending the signaling infor- mation is at the same level as that used to send the data information. Therefore, in accordance with embodiments of the invention, the HDR signaling information is send using the LDR physical layer since its power consumption is low and does not need a high data rate transmission. The MAC frames may be split to data and signaling frames wherein the data frames are' send via the HDR-PHY layer to maintain the data rate requirement, and signal- ing frames are send over the LDR-PHY layer for saving power.

In order to coordinate operation of the two physical layers, an embodiment of the invention provides an adaption layer that deals with the routing, the synchronization, and the power control. The adaption layer coordinates the operation of two different devices using differ- ent protocols (e.g. the HDR protocol and the LDR protocol). It allows having both system functionalities on the same device.

Thus, embodiments of the invention teach the combination of two ultra wide band transceiver platforms into a single ultra wide band platform. The platforms to be integrated comprise the high data rate platform and the low data rate platform and a key component of the resulting combined HDR/LDR structure is, in accordance with an embodiment, the above-described adaption layer. It is an advantage of the invention that when compared to conventional solutions mentioned above, the combined HDR/LDR structure has reduce power constraints, i.e. especially any power input is reduced.

Further embodiments of the invention are defined in the dependent claims. In the following, embodiments of the invention will be described in further detail on the basis of the accompanying drawings, in which:

Fig. 1 shows a block diagram of a high data rate transceiver architecture;

Fig. 2 shows the general MAC frame format in accordance with the ECMA Standard;

Fig. 3 shows a graph illustrating in an HDR system the average power versus the data rate;

Fig. 4 shows a block diagram of a low data rate transceiver architecture;

Fig. 5 shows a super-frame structure used in the LDR system of Fig. 4;

Fig. 6 shows a graph illustrating the energy per-bit consumed by a digital base-band processor used in a LDR system;

Fig. 7 shows a graph illustrating the receiver energy/bit values verses the data rate for

UWB and narrow-band receivers described by Anantha P. Chandrakasan et.al, "Low-Power Impulse UWB Architectures and Circuits", in Proceedings of the IEEE Vol. 97, No. 2,pp. 332-352, February 2009;

Fig. 8 shows a flow diagram of the method for transmitting/receiving payload data in accordance with an embodiment of the invention;

Fig. 9 shows possible HDR/LDR combinations in accordance with embodiments of the invention;

Fig. 10 shows a block diagram of a combined HDR/LDR system in accordance with an embodiment of the invention;

Fig. 11 shows the system of Fig. 10 comprising an adaption layer in accordance with an embodiment of the invention; and

Fig. 12 shows a detailed view of an embodiment of the adaption layer used in the system of Fig. 10. In the subsequent description of embodiments of the present invention, reference will be made to a high data rate system and a low data rate system. As described above, the high data rate system may use data rates of 53.3 Mb/s, 80 Mb/s, 106.7 Mb/s, 160 Mb/s, 200 Mb/s, 320 Mb/s, 400 Mb/s, and 480 Mb/s. Compared to such data rates, the low data rate system described in the present invention has data rates below the above values and, in general, when talking about a high data rate system and a low data rate system, this defines that the high data rate system may transmit data with a rate that is higher than the rate achievable by the low data rate system. Naturally, the invention is not limited to the above- mentioned rates. Rather, other data rates are also covered by the inventive approach.

It is further noted that in the subsequent description of embodiments of the invention, reference is made to transceiver systems. However, the inventive approach is not limited to methods for transmitting/receiving payload data or to transceivers. Rather, the inventive approach may also be implemented only by a method for transmitting payload data, or by a method for receiving payload data, or by a transmitter, or by a receiver.

Fig. 4 depicts an example of a LDR TRX architecture. In the art, LDR (Low Data Rate) ultra wideband systems are known. The operation principles of such systems offer a wide range of applications. In a LDR system the power consumption and size are important is- sues with regard to the system performance, since LDR applications, e.g. sensors and home, office and medical automation equipment, do not mainly depend on high data rate. The LDR- TRX architecture of Fig. 4 comprises a first transceiver 300 operating at a low data rate and comprising a low data rate MAC layer 302 and a low data rate physical layer 304 connected to the antenna ANTj of the transceiver 300. Further, Fig. 4 shows the re- mote transceiver 400 having the antenna ANT₂ and the same internal structure as the transceiver 300. The physical layer includes an RF end which modulates/demodulates the data. The physical layer may use DBPSK (DBPSK = Differential Binary Phase Shift Keying) as a modulation scheme. This modulation scheme provides a good immunity to clock drift and does not require any channel estimation. The demodulation of an incoming signal is performed using a differential correlation between the incoming signal corresponding to the current data symbol and the previous one.

Coherent integration and accumulation modules are added so as to improve the signal to noise ratio before the decision stage. Finally, the demodulated data are provided to a de- framer module that handles the PHY framing aspects, as well as the interface with the MAC layer (see e.g. 1ST PULSERS Phase II D3a3.3: LDR-LT Concept Specifications - PHY and MAC Layers, Jul. 2008). The MAC layer considers a beacon-enabled network which means that the coordinator shall bind its channel time using a classical superframe structure. This superframe is delimited by the transmission of a beacon frame. The superframe is divided into an active portion dedicated to the frame transmission and an inactive portion enabling a timely but peri- odic sleeping mode. During the active period, the superframe begins with the transmission of a Beacon Frame (BF). Then, a Contention Access Period (CAP), which relies on the CSMA/CA protocol (CSMA/CA = Carrier Sense Multiple Access with Collision Avoidance), just follows the BF. An optional Contention Free Period (CFP) can also take place after the CAP. The CFP is divided into Guaranteed Time Slots (GTS), which are defined by a starting slot, a direction (from or towards the coordinator) and an associated device address. A maximum number of 7 GTS may be allowed within this CFP.

In the following, an overview of the LDR-UWB frame structure will be given, the frame structure being based on TDMA (TDMA = Time Division Multiple Access). Each frame is divided into time slots that nodes can utilize to transmit data contention free. Each of these time slots (see Fig. 5) is subdivided into the four following sub-slots: Communication Control (CC), Link setup (LS), Positioning Request (PR) and Data.

A CC message is transmitted to provide the neighboring nodes with the control and syn- chronization information, such as resource availability and slot scheduling table. Within the LS slot, the particular passive node will send a transmission request (TR) to the listening dynamic node to request a data transmission and the dynamic node may provide an acknowledgement in return. The PR slot is used when a node requires the dynamic nodes in the cluster to perform a position estimation operation. The remainder of the time slot (data section) is used for data transfer. Nodes will rotate their duties, being dynamic and passive, for energy conservation; however, a minimum number of nodes must be in dynamic mode within a VC to form the backbone of the system, e.g. a wireless sensor network (WSN). A passive node does not control a time slot and is therefore able to conserve energy as it only listens and transmits when required (see e.g. 1ST PULSERS Phase II D3a3.3 : LDR-LT Concept Specifications - PHY and MAC Layers, Jul. 2008).

Now the power consumption in a LDR-UWB system will be discussed on the basis of power consumption measurement results for a system comprising the PHY chip and the overall MAC design (hardware coprocessor + power PC SOC). Table 2 summarizes the power consumption in the different parts of the PHY, and shows the measured power consumption figures for the different parts of the TCR chip integrated on VI validation platforms Operating Mode Digital Tx Rx I/O

Stand-Alone 10 mW 400 μ\ν 8 mW 11 mW

Baseband active 35 mW 400 W 8 mW 2 mW

Table 2

For the RF part the active Rx (receive) power consumption is in line with comparable technologies (e.g. Zigbee, Bluetooth, etc.). During transmission for the chosen modulation parameters, the active power consumption is 20 times lower than during reception. Thus, the UWB technology is useful for applications where the devices need to transmit more than they receive, like sensor networks for example. When the chip is running in standalone mode, its role is to provide a sampled signal, e.g. to an external FPGA. Since the data flow is quite high (e.g. 1 Gsample per second), the resulting digital and I/Os power con- sumption is high. When running in the baseband mode, the I/Os activity is significantly lowered, and the resulting power consumption is reduced accordingly.

Another investigation for power consumption was done by Anantha P. Chandrakasan et.al, "Low-Power Impulse UWB Architectures and Circuits", in Proceedings of the IEEE Vol. 97, No. 2,pp. 332-352, February 2009. The baseband processor was implemented in a standard- VT 90-nm CMOS process and a 100-Mb/s operation was demonstrated at 0.4 V with an operating frequency of 25 MHz. The breakdown of the energy per bit consumed by the digital baseband processor is shown in Fig. 6. The average energy overhead consumed during acquisition is fixed for a packet. Thus, the shorter the payload, the greater the over- head energy per bit as the overhead energy is amortized over fewer bits. For a 4-kbit packet, using the measured power for acquisition and demodulation provided in Figure 6, the average energy per bit consumed by the digital baseband processor is 20 pJ, with 3 pJ for acquisition and 17 pJ for demodulation. Figure 7 shows the receiver energy/bit as well as the energy/bit of the receiver presented by Anantha P. Chandrakasan et.al, "Low-Power Impulse UWB Architectures and Circuits", in Proceedings of the IEEE Vol. 97, No. 2,pp. 332-352, February 2009. The energy per bit for was calculated as the sum of the receiver energy/bit plus the leakage power component, which causes the energy/bit to rise at lower data rates.

With regard to Figs. 8 to 1 1, embodiments of the present invention are now described in further detail. The inventive approach uses the advantages of the high data rate systems with regard to the transmission of payload data at a high data rate and the advantages of the low data rate system for transmitting signaling information requiring only low power requirements. Fig. 8 shows a flow diagram of the method for transmitting receiving payload data at a high data rate in accordance with an embodiment of the invention.

At step SI 00, it is first of all determined as to whether transmission of data or reception of data occurs.

In the case of transmitting data, as step S200, a data stream including at least one payload data frame and at least one signaling data frame is received. At step S202, the data stream is analyzed for the payload data frames and the signaling data frames. At step S204, it is determined whether the currently analyzed frame in the data stream is a payload data frame or not. In case the currently analyzed frame in the data stream is a payload data frame, the method proceeds to step S206 forwarding the payload data frame to the physical layer of the high data rate system for transmission. In this case, while transmitting the data by the physical layer of the high data rate system, the physical layer of the low data rate system is set into its sleep state. In case it is determined at step S204 that the currently analyzed frame in the data stream is not a payload data frame, the method proceeds to step S208 forwarding the frame to the LDR system. At step S210, the frame is inserted as payload data into the MAC frame of the LDR system and forwarded to the physical layer of the LDR system for transmission at step S212. In accordance with an embodiment, at step S210, on the basis of transmission characteristics for transmitting data via the high data rate system, the required transmission characteristics for the low data rate system are determined such that the signaling frame is correctly transmitted via the low data rate system. More specifically, in one embodiment, the transmission characteristics of the high data rate system comprise a transmission power consumption value and on the basis of this transmission power consumption value, the data rate and power needed by the low data rate system to transmit the signaling frame with the same distance as the high data rate system transmits its data frames, is determined.

Thus, in accordance with the inventive approach for transmitting payload data at a high data rate, the high data rate capacity of the HDR system is used for payload data. However, the signaling data, which does not require the high data rate, is transmitted via the LDR system, thereby reducing the requirements, for example, the power requirements during transmission of the data at the high data rate.

In case it is determined in step SI 00 that data is to be received, the method receives, at step S300, data via the physical layer of the HDR system, while maintaining the physical layer of the LDR system in its sleep state. At step S302, data is received via the physical layer of the LDR system, and at this step, the physical layer of the HDR system is at its sleep state. At step S304, the data carried by the payload portion of the MAC frame of the LDR system is obtained and combined with the data received at step S300 to generate a data stream at step S306 in accordance with the HDR protocol. With regard to the reception mode, it is noted that step S300 and steps S302/S304 may occur in reverse order, i.e. first the data via the LDR system may be received and obtained from the MAC frame followed by reception of the data via the HDR system. The inventive approach of the combined use of the HDR system and the LDR system may be implemented in a method allowing both transmitting and receiving data in a manner as described above with regard to Fig. 8. However, embodiments of the invention may only realize either the method for transmitting the data or the method for receiving the data. Further, it is noted that the method described with regard to Fig. 8 may be realized in a transceiver allowing both transmission and reception of data or it may be realized in separate entities, namely in a transmitter allowing only transmission of data in accordance with the invention or a receiver allowing only reception of data in accordance with the invention. In the following, embodiments of transmitter and/or receiver systems incorporating the inventive approach of combining an HDR system and a LDR system for transmitting pay- load data at a high data rate with improved performance will be described. Fig. 9 shows a general block diagram illustrating possible HDR/LDR combinations. In Fig. 9, the HDR system comprising the HDR-MAC layer and the HDR-PHY layer is shown as well as the LDR system comprising the LDR-MAC layer and the LDR-PHY layer. The arrows between the respective arrows indicate the various combinations that are possible by combining the HDR system and the LDR system within a single transmitter and/or receiver system in accordance with the teachings of the invention. The combined HDR LDR system shown in Fig. 9 may be used as cooperative system or as either HDR or LDR system. The four system operation states are shown in Fig. 9:

1. LDR -UWB system

2. HDR-UWB system

3. HDR/LDR system (the two interfaces not working simultaneously)

4. HDR/LDR system (the two interfaces working simultaneously) The combination of the HDR and LDR UWB system can be separated into two categories - full combined and half combined. The full combined system may be operated as an HDR system and a LDR system at the same time or one at time to support both applications. Fig. 10 illustrates a block diagram of a combined HDR/LDR system in accordance with an embodiment of the invention. Fig. 10 shows a first transceiver 500 comprising the antenna ANTi for communicating with the remote transceiver 600 comprising the antenna ANT₂, the transceiver 600 having the same structure as the transceiver 500. The transceiver 500 comprises a combination of an HDR system and a LDR system. The HDR system com- prises the HDR-MAC 502 that is connected to the HDR physical layer 504 and also to the LDR-MAC layer 506. The LDR-MAC layer 506 is connected to the LDR physical layer 508 and the physical layers 504 and 508 of both systems are connected to the antenna ANTi. The HDR-MAC layer 502 analyzes signals received and, more specifically, it analyzes a data stream for payload data frames and signaling data frames and forwards the payload data frames for transmission to the HDR physical layer 504. The signaling frames are forwarded to the LDR system where the signaling frame is incorporated into the pay- load frame of the MAC layer of the LDR system and forwarded for transmission to the LDR physical layer 508. In accordance with an embodiment of the invention, the combined HDR/LDR system of Fig. 10 is operated in the half combined mode. The half combined system operates as an HDR system that utilizes a LDR-UWB TRX to enhance system performance. The half combined system of this embodiment comprises the HDR system and the MAC-layer and the PHY layer of a LDR system to reduce power consumption in the HDR-UWB TRX. In the HDR system the power consumption is high and generally related to the OFDM modulation scheme and does not really change with the throughput. However, the high throughput in the HDR system results from the data frames size and is not affected by the signaling frames. The power used for sending the signaling information is at the same level as the power level used to send data information. Thus, in accordance with the embodiments of the invention, the HDR signaling information is send using the LDR physical layer since its power consumption is low and does not need a high data rate transmission.

As shown in Fig. 10 the MAC frames are split into data and signaling frames, wherein data is send via the HDR-PHY to maintain the data rate requirement and the signaling frames are send over the LDR-PHY layer for saving power. In order to coordinate the operation of the two physical layers, an adaption layer is provided. This adaption layer deals with routing, synchronization, and power control issues. In the following the adaption layer and its functionality will be described. Fig. 11 shows a further embodiment of the invention in accordance with which the combined HDR LDR system comprises an additional adaption layer. Fig. 11 shows a block diagram of the transceiver system of Fig. 10, wherein the transceiver 500 comprises, in addition, the adaption layer 600. Except for the adaption layer, the transceiver 500 corresponds to the transceiver of Fig. 10. As can be seen from Fig. 11, the adaption layer 600 receives its input from the HDR-MAC layer 502 and comprises two outputs, a first one being connected to the HDR physical layer 504 and a second one being connected to the LDR system and, more specifically, to the LDR-MAC layer 506.

The adaption layer connects the HDR-MAC layer with both physical layers on the other side. Fig. 11 shows a simple HDR/LDR TRX with an adaption layer that splits the traffic at the MAC/PHY interface into data and signaling frames. The adaption layer operates as a DEMUX in the transmission mode and as a MUX in the receiving mode. Its functions in- eludes the recognition of the frame type, the interpolation of the signaling frames to be appropriate for the LDR side (during transmission), the remapping of the LDR-MAC frame (during transmission), the removal of HDR-MAC signaling frame from the LDR- MAC frames (during reception), the power control, and the synchronization. The adaption layer protocol is a translator for the protocols used in the LDR system and the HDR sys- tern.

Fig. 12 shows further details of an embodiment of an adaption layer, as it may be used in the system shown in Fig. 11. The adaption layer 600 comprises a data analysis module 602 that is used for analyzing an input data stream for a data payload information and signaling information. The module 604 is operative either as a demultiplexer in the transmission mode of the transceiver 500 (see Fig. 11) or as a multiplexer during the reception mode of the transceiver 500. In the transmission mode, the demultiplexer module 604 splits the data in the data stream in signaling data and payload data and forwards this information to the module 606 that computes the data rate dependent throughput for the signaling and the payload for the different systems, namely the LDR system 506/508 and the physical layer 504 of the HDR system. In the reception mode, the module 604 combines the information retrieved from the low data rate system and from the physical layer of the high data rate system into a data stream in accordance with the high data rate protocol. The adaption layer protocol coordinates the operation of two different devices using different protocols. It allows having both system functionalities on the same device. The adaption layer protocol starts with a data analysis of received MAC frames and on the basis of the frame type will recognize whether a frame is a signaling frame or a data frame. Based on the frame type the DEMUX switches its output to the next stage. In this stage, in accordance with an embodiment, the adaption protocol computes the required power to transmit the LDR frames using the power-distance relation in the HDR and LDR TRXs. The computation starts with an observation of the throughput, the distance and the power relation in the HDR system that may be stored in the HDR/LDR conditioning stage. On the basis of the HDR power consumption value the LDR data rate and power needed to transmit the signaling frame with the same distance as the associated transmission of the data by the HDR TRX is determined. At the final stage the protocol will route the signaling frame for insertion as payload into the LDR MAC frames and send it over the interface. In the data frame case, the adaption protocol forwards the frames to the HDR physical layer with the data rate and power defined by the HDR-MAC layer.

In the two physical layers in the HDR/LDR TRX of this embodiment, the operation states for both parts are controlled by the adaption layer. In the data traffic mode, the HDR forwards the HDR-MAC layer frames and changes the HDR-PHY layer state from sleep to ready and to transmit or receive the LDR-PHY layer is changed to the sleep state. In the signaling traffic mode the adaption layer informs the LDR to switch the LDR-PHY layer to the ready state to be prepared for the transmission or the receipt state. Table 4 shows the states of two layers.

Table 3

One of the two systems is allowed to be in active state and this is a direct result of using HDR-MAC frames contents as controller for switching process.

Although some aspects have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.

Depending on certain implementation requirements, embodiments of the invention can be implemented in hardware or in software. The implementation can be performed using a digital storage medium, for example a floppy disk, a DVD, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed. Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.

Generally, embodiments of the invention can be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer. The program code may for example be stored on a machine readable carrier. Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier.

In other words, an embodiment of the inventive method may, therefore, be

• a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer, or

· a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein, or

• a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet.

A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein. A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

In some embodiments, a programmable logic device (for example a field programmable gate array) may be used to perform some or all of the functionalities of the methods de- scribed herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods described herein. Generally, the methods are preferably performed by any hardware apparatus. The above described embodiments are merely illustrative for the principles of the present invention. It is understood that modifications and variations of the arrangements and the details described herein will be apparent to others skilled in the art. It is the intent, therefore, to be limited only by the scope of the impending patent claims and not by the specific details presented by way of description and explanation of the embodiments herein.

Claims

A method for transmitting or receiving payload data with a high data rate in a system comprising a high data rate platform (502, 504) and a low data rate platform (506, 508), the method comprising: transmitting (S206) or receiving (S300) the payload data via the high data rate platform (502, 504); and transmitting (S212) or receiving (S302) signaling data associated with the payload data via the low data rate platform (506, 508).

The method of claim 1 for transmitting the payload data and comprising the following steps: analyzing (S202) a data stream, the data stream comprising at least one data frame and at least one signaling frame; in case a signaling frame is detected in the data stream, switching (S204, S208- S212) the signaling frame to the low data rate platform (506, 508); and in case a data frame is detected in the data stream, switching (S204, S206) the data frame to the high data rate platform (502, 504).

The method of claim 2, wherein the low data rate platform (506, 508) is deactivated while transmitting (S206) the payload data via the high data rate platform (502, 504) and wherein the high data rate platform (502, 504) is deactivated while transmitting (S212) the signaling data via the low data rate platform (506, 508).

The method of claim 2 or 3, wherein transmitting (S208-S212) the signaling data comprises inserting (S210) the signaling frame into a payload frame of the low rate data platform (506, 508).

The method of one of claims 2 to 4, further comprising: on the basis of transmission characteristics for transmitting data via the high data rate platform (502, 504), determining the required transmission characteristics of the low data rate platform (506, 508) for correctly transmitting the signaling frame via the low data rate platform (506, 508).

6. The method of claim 5, wherein the transmission characteristics of the high data rate platform (502, 504) comprise a transmission power consumption value, and wherein the low data rate platform (506, 508) determines, on the basis of the transmission power consumption value of the high data rate platform (502, 504), a data rate and a power needed to transmit the signaling frame with the same distance as the high data rate platform (502, 504).

7. The method of one of claims 1 to 6, wherein the high data rate platform (502, 504) and the low data rate platform (506, 508) operate in accordance with a high data rate protocol and a low data rate protocol, respectively, each platform comprising a MAC layer (502, 506) and a PHY layer (504, 508), the method further comprising: receiving (S200) and analyzing (S202) a data stream to be transmitted in accordance with the high data rate protocol; forwarding (S206) the data frame to the PHY layer (504) of the high data rate platform for transmission; forwarding (S208) the signaling frame to the low data rate platform for inserting (S210) the signaling frame as a payload for a MAC frame of the MAC layer (506) of the low data rate platform; and forwarding (SI 12) the MAC frame of the low data rate protocol to the PHY layer (508) of the low data rate platform for transmission.

8. The method of claim 1 for receiving the payload data and comprising the following steps: receiving (S300), via the high data rate platform (502, 504), at least one data frame; receiving (S302), via the low data rate platform (506, 508), at least one signaling frame; and combining (S306) the data frame and the signaling frame into a common data stream in accordance with the high data rate platform.

The method of claim 8, wherein the high data rate platform (502, 504) and the low data rate platform (506, 508) operate in accordance with a high data rate protocol and a low data rate protocol, respectively, each platform comprising a MAC layer (502, 506) and a PHY layer (504, 508), the method further comprising: receiving, (S300) via the PHY layer (504) of the high data rate platform, a data frame; receiving, (S302) via the PHY layer (508) of the low data rate platform, a MAC frame including, as a payload, a signaling frame; retrieving (S304) the signaling frame from the MAC layer (506); and combining (S306) the data frame and the retrieved signaling frame for generating a data stream in accordance with the high data rate protocol.

A computer readable medium comprising a plurality of instructions for carrying out the method of one of claims 1 to 9 when executing the instructions by a computer.

A transmitter for transmitting payload data with a high data rate, the transmitter comprising: a high data rate platform (502, 504); a low data rate platform (506, 508); and a controller (600) configured to transmit the payload data via the high data rate platform (502, 506), and to transmit signaling data associated with the payload data via the low data rate platform (506, 508).

The transmitter of claim 11 , wherein the controller (600) is configured to analyze a data stream received at the transmitter, the data stream comprising at least one data frame and at least one signaling frame; switch a signaling frame to the low data rate platform (506, 508) in case the signaling frame is detected in the data stream; and switch a data frame to the high data rate platform (502, 504) in case the data frame is detected in the data stream.

13. The transmitter of claim 12, wherein the controller (600) is configured to deactivate the low data rate platform (506, 508) while transmitting the payload data via the high data rate platform (502, 504), and to deactivate the high data rate platform (502, 504) while transmitting the signaling data via the low data rate platform (504, 508).

14. The transmitter of claim 12 or 13, wherein for transmitting the signaling data, the controller (600) causes inserting the signaling frame into a payload frame of the low rate data platform (506, 508).

15. The transmitter of one of claims 12 to 14, wherein the controller (600) is further configured to determine the required transmission characteristics of the low data platform (506, 508) for correctly transmitting the signaling frame via the low data rate platform (506, 508) on the basis of transmission characteristics for transmitting data via the high data rate platform (502, 504).

16. The transmitter of claim 15, wherein the transmission characteristics of the high data rate platform (502, 504) comprises a transmission power consumption value, and wherein the controller (600) is configured to determine, for the low data rate platform (506, 508), a data rate and a power needed to transmit the signaling frame with the same distance as the high data rate platform (502, 504), on the basis of the transmission power consumption value of the high data rate platform (502, 504).

17. The transmitter of one of claims 12 to 16, wherein the high data rate platform (502, 504) and the low data rate platform (506, 508) operate in accordance with a high data rate protocol and a low data rate protocol, respectively, each platform comprising a MAC layer (502, 504) and a PHY layer (506, 508); and the controller (600) is configured to receive and analyze a data stream to be transmitted in accordance with the high data rate protocol, forward the data frame to the PHY layer (504) of the high data rate platform for transmission, forward the signaling frame to the low data rate platform (506, 508) for inserting the signaling frame as a pay load into a MAC frame of the MAC layer (506) of the low data rate platform, and forward the MAC frame of the low data rate protocol to the PHY layer (508) of the low data rate platform for transmission.

18. A receiver for receiving payload data with a high data rate, the receiver comprising: a high data rate platform (502, 504); a low data rate platform (506, 508); and a controller (600) configured to receive the payload data via the high data rate platform (502, 504), and to receive signaling data associated with the payload data via the low data rate platform (506, 508).

19. The receiver of claim 18, wherein the controller (600) is configured to receive, via the high data rate platform (502, 504), at least one data frame, receive, via the low data rate platform (506, 508), at least one signaling frame; and combine the data frame and the signaling frame into a common data stream in accordance with the high data rate platform.

20. The receiver of claim 19, wherein the high data rate platform (502, 504) and the low data rate platform (506, 508) operate in accordance with a high data rate protocol and a low data rate protocol, respectively, each platform comprising a MAC layer (502, 504) and a PHY layer (506, 508); and the controller (600) is configured to receive, via the PHY layer (504) of the high data rate platform, a data frame; receive, via the PHY layer (508) of the low data rate platform, a MAC frame including, as a payload, a signaling frame; retrieve the signaling frame from the MAC layer (506), and combine the data frame and the retrieved signaling frame for generating a data stream in accordance with the high data rate protocol.

An adaption layer (600) for routing a data stream between a MAC layer (502) of a high data rate platform and a PHY layer (504) of the high data rate platform or between the MAC layer (502) of the high data rate platform and a MAC layer (506) of a low data rate platform, the adaption layer (600) being configured to analyze (S202) a data stream to be transmitted in accordance with a high data rate protocol, to route (S204, S206) a payload data frame in the data stream to the PHY layer (504) of the high data rate platform for transmission, and to route (S204, S208-S212) a signaling frame in the data stream to the MAC layer (506) of the low data rate platform for transmission.

The adaption layer of claim 21, configured to determine the required transmission characteristics of the low data rate platform (506, 508) for correctly transmitting the signaling frame via the low data rate platform (506, 508) on the basis of the transmission characteristics for transmitting data via the high data rate platform (502, 504).

The adaption layer of claim 22, wherein the transmission characteristics of the high data rate platform (502, 504) comprise a transmission power consumption value, the adaption layer (600) being further configured to determine, for the low data rate platform (506, 508), a data rate and a power needed to transmit the signaling frame with the same distance as the high data rate platform (502, 504), on the basis of the transmission power consumption value of the high data rate platform (502, 504).

24. The adaption layer of one of claims 21 to 23, being configured to receive (S300) from the PHY layer (504) of the high data rate platform, a payload frame; receive (S302) from the MAC layer (506) of the low data rate platform, a signaling frame, and combine the received payload frame and the received signaling frame to a data stream in accordance with the high data rate protocol.