RFWiMAX SBC-REQ and SBC-RSP: Basic Capability Negotiation
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This page details the fixed WiMAX basic capability negotiation between a Base Station (BS) and a Subscriber Station (SS), as defined by the IEEE 802.16 MAC layer specifications. Specifically, it covers the WiMAX SBC-REQ and SBC-RSP message formats. The primary purpose is for the SS to inform the BS of its fundamental capabilities.
The SS transmits the SBC-REQ, which the BS receives. Upon receipt, the BS responds with an SBC-RSP message. The process unfolds as follows:
- After ranging completes, the BS waits for the SBC-REQ message from the SS.
- If the BS doesn’t receive the SBC-REQ message within the time specified by timer T9, it releases and ages out the allocated Basic and Primary Management CIDs.
Important Timers:
- Timer T17: The time allowed for the SS to complete authorization and key exchange.
- Timer T9: Registration timeout.
WiMAX SBC-REQ
The following table provides a typical example of WiMAX SBC-REQ message values transmitted by a WiMAX-compliant SS.
| SBC REQ field | Example Value |
|---|---|
| Generic mac header(6 bytes) | 0x00, 0x40, 0x33, 0x00 ,0x08, 0xff |
| SBC REQ message type | 0x1a |
| BW Allocation support(TLV format ) | 0x01,0x01,0x00 |
| Capabilities for Construction & Transmission of MAC PDUs(TLV) | 0x04,0x01,0x03 |
| SS Transition Gap(TLV) | 0x02,0x02,0x00,0x00 |
| Max. Transmit Power(TLV) | 0x03,0x04,0x00,0x00,0x00,0x00 |
| Current Transmit Power(TLV) | 0x93,0x01,0x00 |
| OFDM SS FFT sizes (TLV) | 0x96,0x01,0x01 |
| OFDM SS demodulator(TLV) | 0x97,0x01,0x01 |
| OFDM SS modulator(TLV) | 0x98,0x01,0x01 |
| OFDM SS TC sublayer support(TLV) | 0x9a,0x01,0x00 |
| CRC(4 bytes) | 0x3a,0xb6,0x3e,0x60 |
WiMAX SBC-RSP
The subsequent table shows a typical example of WiMAX SBC-RSP message values transmitted by the BS in response to the SBC-REQ received from the SS.
| SBC RSP field | Example Value |
|---|---|
| Generic MAC Header(6 bytes) | 0x00, 0x40, 0x2a, 0x00, 0x08, 0x67 |
| SBC_RSP msg type | 0x1b |
| Bandwidth allocation support(TLV) | 0x01,0x01,0x00 |
| capablities for construction & transmission of MAC pdus(T) | 0x04,0x01,0x03 |
| subscriber transition gaps(T) | 0x02,0x02,0x32,0x32 |
| PKM flow control(T) | 0x0f,0x01,0x00 |
| Authorization policy support(T) | 0x10,0x01,0x00 |
| max. no of supported security associations(T) | 0x11,0x01,0x00 |
| OFDM SS FFT sizes(T) | 0x96,0x01,0x01 |
| OFDM SS Demodulator(T) | 0x97,0x01,0x01 |
| OFDM SS modulator(T) | 0x98,0x01,0x01 |
| OFDM SS TC sublayer support(T) | 0x9a,0x01,0x00 |
| CRC | 0x27,0x53,0x80,0xb6 |
