Patent Grant
7149818
The present invention relates to data transmission in a network, and more particularly to the rate of data transmission in the network.
Home networks are becoming more common and desirable for connecting computers within a home. One type of home network is the home phone line network which uses telephone lines typically installed in residential homes for communication between computers in the home. The Home Phone Line Networking Alliance (HPNA) has published a specification to standardize the behavior of home phone line networks. The current HPNA specification is version 2.0 (“HPNA 2.0”).
Because conditions on the phone lines vary, the HPNA 2.0 allows the data transmission rate between two stations in the network to be changed, according to the transmission error rate. If a data transmission rate is too fast for the line condition, then there can be a high level of errors in the frames received. If the data transmission rate is too slow for the line condition, then the data transmission rate is not optimized. The data transmission rate is determined by a payload encoding (PE). The PE is defined as the bit loading (bits/symbol) multiplied by the symbol rate (symbols/sec). The goal for HPNA 2.0 is to have a transmission error rate less than 10−4.
In the HPNA 2.0, the PHY 110 receives a frame with a PE and calculates a mean square error (MSE) for this frame. This MSE is sent to the upper layer driver software 204. After receiving the MSE's for frames within a history window, defined in HPNA 2.0 as sixteen frames, the driver software 204 calculates an average mean square error (AMSE). This AMSE is compared with the acceptable AMSE range for the current PE. If the AMSE is within the range, then the station continues to transmit at the current PE. If the AMSE is below the range, then the station can use a higher PE. If the AMSE is above the range, then the station should use a lower PE. The driver software 204 then sends a packet to another station informing it of the data transmission rate change. The other station responds by generating test frames to assist the station in selecting the most appropriate PE. This is referred to as “rate negotiation”. However, HPNA 2.0 does not specify how the PHY MSE reaches the upper level driver software 204.
Accordingly, there exists a need for a method for communicating a PHY MSE to an upper layer driver software for rate negotiation. The present invention addresses such a need.
A method for communicating a Physical Layer (PHY) mean square error (MSE) to an upper layer device driver includes: receiving a frame by the PHY; computing a MSE for the frame by the PHY; sending the MSE and the frame to a Media Access Control (MAC); inserting the MSE into a frame status frame (FSF) associated with the frame by the MAC; and sending the frame and the FSF to the upper layer driver software. With access to the PHY MSE, the upper layer driver software can compute the average mean square error (AMSE) and determine if a change in the payload encoding (PE), or data transmission rate, should be negotiated. In this manner, the data transmission rate can be optimized while maintaining a low error rate.
The present invention provides a method for communicating a PHY MSE to an upper layer driver software for rate negotiation. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.
To more particularly describe the features of the present invention, please refer to
The Receive Data Path 302 receives data packets from the PHY 110 and sends data packets to the MII 106. In the preferred embodiment, after each data packet sent by the Receive Data Path 302, another packet, referred to herein as a “frame status frame” (FSF), is sent immediately following. The frame status frame contains certain status information required by subsequent processes. The FSF Generation block 318 in the Receive Data Path 302 generates the FSF of each frame.
The Transmit Data Path 304, which receives data packets from the MII 106 and transmits them to the PHY 110.
The DFPQ 306 and the BEB 308 provide collision resolution. The DFPQ 306 provides collision resolution for the 10 mpbs data rate, while the BEB 308 provides collision resolution for the 1 mpbs data rate. In the preferred embodiment, the PHY 110 will provide a collision detect signal. Either the DFPQ 306 or the BEB 308 will then attempt to resolve the collision.
The Link Integrity 310 monitors the physical network conditions. In the preferred embodiment, the Link Integrity 310 updates a link status bit in a link register. The Link Integrity 310 also sends link packets in accordance with HPNA 2.0.
The RRCF 314 sends a RRCF whenever the MAC 300 transitions between data rates. The RRCF is used to perform the rate negotiation function, i.e., to determine what is the data rate to communicate between different stations in a home phone line network.
The registers and MIB counters 316 provides programmability to the MAC 300 and handles error event counting.
The Network State 312 in accordance with the present invention monitors the current mode of the MAC 300, i.e., whether the MAC 300 is operating in the 1M8 mode, the V1M2 mode, or the 10M8 mode.
Once the AMSE is computed, the AMSE is compared with the acceptable AMSE range for the current PE. If the AMSE is within the range, then the station continues to transmit at the current PE. If the AMSE is below the range, then the station negotiates a higher PE. If the AMSE is above the range, then the station negotiates a lower PE.
A method for communicating a PHY mean square error (MSE) to an upper layer driver software for rate negotiation has been disclosed. With access to the PHY MSE, the upper layer driver software can compute the average mean square error (AMSE) and determine if a change in the payload encoding (PE), or data transmission rate, should be negotiated. In this manner, the data transmission rate can be optimized while maintaining a low error rate.
Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.
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| 20030018821 A1 | Jan 2003 | US |
