diff --git a/core/net/mac/ctdma_mac.c b/core/net/mac/ctdma_mac.c
new file mode 100644
index 000000000..2f39d3f63
--- /dev/null
+++ b/core/net/mac/ctdma_mac.c
@@ -0,0 +1,243 @@
+/*
+ * Copyright (c) 2007, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ * $Id: ctdma_mac.c,v 1.1 2007/09/18 10:36:36 fros4943 Exp $
+ */
+
+#include "contiki.h"
+#include "net/mac/ctdma_mac.h"
+#include "net/rime/rimebuf.h"
+#include "net/uip-fw.h"
+#include "net/rime/ctimer.h"
+#include "net/rime.h"
+#include "lib/memb.h"
+#include "lib/list.h"
+#include "dev/leds.h"
+#include "node-id.h"
+
+#include <string.h>
+#include <stdio.h>
+
+#define DEBUG 1
+#if DEBUG
+#define DLEDS_ON(x) leds_on(x)
+#define DLEDS_OFF(x) leds_off(x)
+#define DLEDS_TOGGLE(x) leds_toggle(x)
+#define PRINTF(...) printf(__VA_ARGS__)
+#else
+#define DLEDS_ON(x)
+#define DLEDS_OFF(x)
+#define DLEDS_TOGGLE(x)
+#define PRINTF(...)
+#endif
+
+/* TDMA */
+#define NR_SLOTS 3
+#define SLOT_LENGTH (CLOCK_SECOND/3)
+#define GUARD_PERIOD (CLOCK_SECOND/12)
+
+#define MY_SLOT (node_id % NR_SLOTS)
+#define PERIOD_LENGTH CLOCK_SECOND
+
+/* Buffers */
+#define NUM_PACKETS 8
+u8_t lastqueued = 0;
+u8_t nextsend = 0;
+u8_t freeslot = 0;
+struct queuebuf* data[NUM_PACKETS];
+int id[NUM_PACKETS];
+
+static struct ctimer ctimer;
+u8_t timer_on = 0;
+
+static const struct radio_driver *radio;
+static void (* receiver_callback)(const struct mac_driver *);
+static int id_counter = 0;
+static int sent_counter = 0;
+
+/*---------------------------------------------------------------------------*/
+static void
+transmitter(void *ptr)
+{
+  clock_time_t now, rest, period_start, slot_start;
+
+  /* Calculate slot start time */
+  now = clock_time();
+  rest = now % PERIOD_LENGTH;
+  period_start = now - rest;
+  slot_start = period_start + MY_SLOT*SLOT_LENGTH;
+
+  /* Check if we are inside our slot */
+  if (now < slot_start ||
+      now > slot_start + SLOT_LENGTH - GUARD_PERIOD)
+  {
+    PRINTF("TIMER We are outside our slot: %u != [%u,%u]\n", now, slot_start, slot_start + SLOT_LENGTH);
+    while (now > slot_start + SLOT_LENGTH - GUARD_PERIOD)
+    {
+      slot_start += PERIOD_LENGTH;
+    }
+    
+    PRINTF("TIMER Rescheduling until %u\n", slot_start);
+    ctimer_set(&ctimer, slot_start - clock_time(), transmitter, NULL);
+    return;
+  }
+
+  /* Transmit queued packets */
+  while (nextsend != freeslot)
+  {
+    PRINTF("RADIO Transmitting packet #%i\n", id[nextsend]);
+    if(!radio->send(
+        queuebuf_dataptr(data[nextsend]), 
+        queuebuf_datalen(data[nextsend])))
+    {
+      sent_counter++;
+      PRINTF("RADIO Transmit OK for #%i, total=%i\n", id[nextsend], sent_counter);
+      DLEDS_TOGGLE(LEDS_GREEN);
+    }
+    else
+    {
+      PRINTF("RADIO Transmit failed for #%i, total=%i\n", id[nextsend], sent_counter);
+      DLEDS_TOGGLE(LEDS_RED);
+    }
+
+    nextsend = (nextsend + 1) % NUM_PACKETS;
+
+    /* Recalculate new slot */
+    if (clock_time() > slot_start + SLOT_LENGTH - GUARD_PERIOD)
+    {
+      PRINTF("TIMER No more time to transmit\n");
+      break;
+    }
+  }
+
+  /* Calculate time of our next slot */
+  slot_start += PERIOD_LENGTH;
+  PRINTF("TIMER Rescheduling until %u\n", slot_start);
+  ctimer_set(&ctimer, slot_start - clock_time(), transmitter, NULL);
+}
+/*---------------------------------------------------------------------------*/
+static int
+send(void)
+{
+  id_counter++;
+  
+  /* Clean up already sent packets */
+  while (lastqueued != nextsend)
+  {
+    PRINTF("BUFFER Cleaning up packet #%i\n", id[lastqueued]);
+    queuebuf_free(data[lastqueued]);
+    data[lastqueued] = NULL;
+
+    lastqueued = (lastqueued + 1) % NUM_PACKETS;
+  }
+  
+  if ((freeslot + 1) % NUM_PACKETS == lastqueued)
+  {
+    PRINTF("BUFFER Buffer full, dropping packet #%i\n", (id_counter+1));
+    return UIP_FW_DROPPED;
+  }
+
+  /* Allocate queue buf for packet */
+  data[freeslot] = queuebuf_new_from_rimebuf();
+  id[freeslot] = id_counter;
+  if (data[freeslot] == NULL)
+  {
+    PRINTF("BUFFER Queuebuffer full, dropping packet #%i\n", id[freeslot]);
+    return UIP_FW_DROPPED;
+  }
+  PRINTF("BUFFER Wrote packet #%i to buffer \n", id[freeslot]);
+
+  freeslot = (freeslot + 1) % NUM_PACKETS;
+  
+  if (!timer_on) 
+  {
+    PRINTF("TIMER Starting timer\n");
+    ctimer_set(&ctimer, CLOCK_SECOND, transmitter, NULL);
+    timer_on = 1;
+  }
+
+  return UIP_FW_OK; /* TODO Return what? */
+}
+/*---------------------------------------------------------------------------*/
+static void
+input(const struct radio_driver *d)
+{
+  receiver_callback(&ctdma_mac_driver);
+}
+/*---------------------------------------------------------------------------*/
+static int
+read(void)
+{
+  int len;
+  rimebuf_clear();
+  len = radio->read(rimebuf_dataptr(), RIMEBUF_SIZE);
+  rimebuf_set_datalen(len);
+  return len;
+}
+/*---------------------------------------------------------------------------*/
+static void
+set_receive_function(void (* recv)(const struct mac_driver *))
+{
+  receiver_callback = recv;
+}
+/*---------------------------------------------------------------------------*/
+static int
+on(void)
+{
+  return radio->on();
+}
+/*---------------------------------------------------------------------------*/
+static int
+off(void)
+{
+  return radio->off();
+}
+/*---------------------------------------------------------------------------*/
+void
+ctdma_mac_init(const struct radio_driver *d)
+{
+  int i;
+  for (i=0; i < NUM_PACKETS; i++)
+  {
+    data[i] = NULL;
+  }
+
+  radio = d;
+  radio->set_receive_function(input);
+  radio->on();
+}
+/*---------------------------------------------------------------------------*/
+const struct mac_driver ctdma_mac_driver = {
+  send,
+  read,
+  set_receive_function,
+  on,
+  off,
+};
diff --git a/core/net/mac/ctdma_mac.h b/core/net/mac/ctdma_mac.h
new file mode 100644
index 000000000..22e1f6dae
--- /dev/null
+++ b/core/net/mac/ctdma_mac.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2007, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the Contiki operating system.
+ *
+ * $Id: ctdma_mac.h,v 1.1 2007/09/18 10:36:36 fros4943 Exp $
+ */
+
+#ifndef __CTDMA_MAC_H__
+#define __CTDMA_MAC_H__
+
+#include "net/mac/mac.h"
+#include "dev/radio.h"
+
+extern const struct mac_driver ctdma_mac_driver;
+
+void ctdma_mac_init(const struct radio_driver *r);
+
+#endif /* __CTDMA_MAC_H__ */